497

Fidelity (logo) Investments®|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| FPCMS
82 Devonshire Street
Boston MA 02109-3614
617 563 7000

||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| January 18, 2013

U.S. Securities & Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Attention: File Room

Re:	Fidelity Salem Trust (the trust):
	Spartan Global ex U.S. Index Fund Spartan Emerging Markets Index Fund (the funds)
	File Nos. 002-41839 and 811-02105

__________________________________________________________________________

Ladies and Gentlemen:

Transmitted herewith for filing pursuant to Rule 497(e) under the Securities Act of 1933, as amended, are exhibits containing interactive data format risk/return summary information for the funds' Prospectuses. The purpose of this filing is to submit the 497 filing in XBRL for the funds'.

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||	Very truly yours,
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||	/s/Kate Paquette
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||	Kate Paquette
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||	Legal Product Group

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY SALEM STREET TRUST

Prospectus Date

rr_ProspectusDate

Dec. 29, 2012

Inst Adv Inst | Spartan Global ex U.S. Index Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

fsst8_SupplementTextBlock

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Institutional Class and Fidelity Advantage^® Institutional Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage® Institutional Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.28%	0.25%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 75	$ 65
5 years	$ 142	$ 126
10 years	$ 341	$ 303

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage Institutional Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.23%	0.20%
Fee waiver/or expense reimbursementA	0.10%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 63	$ 54
5 years	$ 119	$ 102
10 years	$ 282	$ 245

XML

Inst Adv Inst | Spartan Global ex U.S. Index Fund

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Institutional Class and Fidelity Advantage^® Institutional Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage® Institutional Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.28%	0.25%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 75	$ 65
5 years	$ 142	$ 126
10 years	$ 341	$ 303

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage Institutional Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.23%	0.20%
Fee waiver/or expense reimbursementA	0.10%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 63	$ 54
5 years	$ 119	$ 102
10 years	$ 282	$ 245

XML

Adv Inv | Spartan Emerging Markets Index Fund

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Investor Class and Fidelity Advantage^® Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage® Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.50%	1.50%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.21%	0.10%
Total annual operating expenses	0.46%	0.35%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.31%	0.20%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.31% and 0.20%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Investor Class	Fidelity Advantage Class
1 year	$ 32	$ 20
3 years	$ 133	$ 97
5 years	$ 243	$ 181
10 years	$ 565	$ 428

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.00%	1.00%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.14%	0.08%
Total annual operating expenses	0.34%	0.28%
Fee waiver/or expense reimbursementA	0.12%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.22%	0.18%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.22% and 0.18%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Investor Class	Fidelity Advantage Class
1 year	$ 23	$ 18
3 years	$ 97	$ 79
5 years	$ 179	$ 147
10 years	$ 419	$ 345

XML

Inst Adv Inst | Spartan Emerging Markets Index Fund

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Institutional Class and Fidelity Advantage^® Institutional Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage® Institutional Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.28%	0.25%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 75	$ 65
5 years	$ 142	$ 126
10 years	$ 341	$ 303

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage Institutional Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.23%	0.20%
Fee waiver/or expense reimbursementA	0.10%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 63	$ 54
5 years	$ 119	$ 102
10 years	$ 282	$ 245

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY SALEM STREET TRUST

Prospectus Date

rr_ProspectusDate

Dec. 29, 2012

Inst Adv Inst | Spartan Emerging Markets Index Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

fsst8_SupplementTextBlock

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Institutional Class and Fidelity Advantage^® Institutional Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage® Institutional Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.28%	0.25%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 75	$ 65
5 years	$ 142	$ 126
10 years	$ 341	$ 303

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Institutional Class	Fidelity Advantage Institutional Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.03%	0.00%
Total annual operating expenses	0.23%	0.20%
Fee waiver/or expense reimbursementA	0.10%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.13%	0.10%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Institutional Class and Fidelity Advantage Institutional Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.13% and 0.10%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Institutional Class	Fidelity Advantage Institutional Class
1 year	$ 13	$ 10
3 years	$ 63	$ 54
5 years	$ 119	$ 102
10 years	$ 282	$ 245

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY SALEM STREET TRUST

Prospectus Date

rr_ProspectusDate

Dec. 29, 2012

Adv Inv | Spartan Emerging Markets Index Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

fsst8_SupplementTextBlock

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Investor Class and Fidelity Advantage^® Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage® Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.50%	1.50%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.21%	0.10%
Total annual operating expenses	0.46%	0.35%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.31%	0.20%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.31% and 0.20%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Investor Class	Fidelity Advantage Class
1 year	$ 32	$ 20
3 years	$ 133	$ 97
5 years	$ 243	$ 181
10 years	$ 565	$ 428

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.00%	1.00%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.14%	0.08%
Total annual operating expenses	0.34%	0.28%
Fee waiver/or expense reimbursementA	0.12%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.22%	0.18%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.22% and 0.18%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Investor Class	Fidelity Advantage Class
1 year	$ 23	$ 18
3 years	$ 97	$ 79
5 years	$ 179	$ 147
10 years	$ 419	$ 345

XML

Document and Entity Information	12 Months Ended
	Dec. 29, 2012
Risk/Return:
Document Type	Other
Document Period End Date	Oct. 31, 2012
Registrant Name	FIDELITY SALEM STREET TRUST
Central Index Key	0000035315
Amendment Flag	false
Document Creation Date	Dec. 31, 2012
Document Effective Date	Dec. 29, 2012
Prospectus Date	Dec. 29, 2012

XML

Adv Inv | Spartan Global ex U.S. Index Fund

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Investor Class and Fidelity Advantage^® Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage® Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.50%	1.50%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.21%	0.10%
Total annual operating expenses	0.46%	0.35%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.31%	0.20%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.31% and 0.20%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Investor Class	Fidelity Advantage Class
1 year	$ 32	$ 20
3 years	$ 133	$ 97
5 years	$ 243	$ 181
10 years	$ 565	$ 428

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.00%	1.00%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.14%	0.08%
Total annual operating expenses	0.34%	0.28%
Fee waiver/or expense reimbursementA	0.12%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.22%	0.18%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.22% and 0.18%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Investor Class	Fidelity Advantage Class
1 year	$ 23	$ 18
3 years	$ 97	$ 79
5 years	$ 179	$ 147
10 years	$ 419	$ 345

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY SALEM STREET TRUST

Prospectus Date

rr_ProspectusDate

Dec. 29, 2012

Adv Inv | Spartan Global ex U.S. Index Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

fsst8_SupplementTextBlock

Supplement to the 
Spartan^® Emerging Markets Index Fund and 
Spartan Global ex U.S. Index Fund
Investor Class and Fidelity Advantage^® Class
December 29, 2012
Prospectus

Effective January 1, 2013, the following information replaces the similar information for Spartan^® Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 3.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage® Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.50%	1.50%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.25%	0.25%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.21%	0.10%
Total annual operating expenses	0.46%	0.35%
Fee waiver/or expense reimbursementA	0.15%	0.15%
Total annual operating expenses after fee waiver/or expense reimbursement	0.31%	0.20%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.31% and 0.20%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Emerging Markets Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 4.

	Investor Class	Fidelity Advantage Class
1 year	$ 32	$ 20
3 years	$ 133	$ 97
5 years	$ 243	$ 181
10 years	$ 565	$ 428

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 7.

Shareholder fees (fees paid directly from your investment)
	Investor Class	Fidelity Advantage Class
Redemption fee on shares held less than 90 days (as a % of amount redeemed)	1.00%	1.00%

Annual class operating expenses
(expenses that you pay each year as a % of the value of your investment)

	Investor Class	Fidelity Advantage Class
Management fee	0.20%	0.20%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.14%	0.08%
Total annual operating expenses	0.34%	0.28%
Fee waiver/or expense reimbursementA	0.12%	0.10%
Total annual operating expenses after fee waiver/or expense reimbursement	0.22%	0.18%

^A Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Investor Class and Fidelity Advantage Class of the fund to the extent that total operating expenses (excluding interest, taxes, certain securities lending costs, brokerage commissions, extraordinary expenses, and acquired fund fees and expenses, if any), as a percentage of their respective average net assets, exceed 0.22% and 0.18%, respectively. These arrangements will remain in effect through December 31, 2013. FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees.

Effective January 1, 2013, the following information replaces the similar information for Spartan Global ex U.S. Index Fund under the heading "Fee Table" in the "Fund Summary" section on page 8.

	Investor Class	Fidelity Advantage Class
1 year	$ 23	$ 18
3 years	$ 97	$ 79
5 years	$ 179	$ 147
10 years	$ 419	$ 345

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	FIDELITY SALEM STREET TRUST
Prospectus Date	rr_ProspectusDate	Dec. 29, 2012
Document Creation Date	dei_DocumentCreationDate	Dec. 31, 2012