497

Bingham McCutchen LLP

One Federal Street

Boston, Massachusetts 02110

December 7, 2012

VIA EDGAR

Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Re: Western Asset Mortgage Backed Securities Fund (the “Fund”), a series of Legg Mason Partners

Income Trust (the “Registrant”)

Securities Act File No. 2-96408

Investment Company Act File No. 811-04254

Ladies and Gentlemen:

On behalf of the Registrant and pursuant to Rule 497(e) under the Securities Act of 1933, as amended, attached for filing are exhibits containing in interactive data format the risk/return summary information that appears in a supplement dated November 28, 2012 to the Fund’s Prospectus dated August 1, 2012.

Any questions or comments on the filing should be directed to the undersigned at (617) 951-8267.

Sincerely,

/s/ Barry N. Hurwitz

Barry N. Hurwitz

Enclosures

cc: Rosemary D. Emmens, Legg Mason & Co., LLC

XML

LEGG MASON PARTNERS INCOME TRUST

SUPPLEMENT DATED NOVEMBER 28, 2012

TO THE SUMMARY PROSPECTUS AND PROSPECTUS,

EACH DATED AUGUST 1, 2012, OF

WESTERN ASSET MORTGAGE BACKED SECURITIES FUND

Effective as of January 1, 2013, the following text replaces any inconsistent information in the section titled “Fees and expenses of the fund” in the fund’s Summary Prospectus and Prospectus:

Shareholder fees (fees paid directly from your investment)
	Class 1
Maximum sales charge (load) imposed on purchases (as a % of offering price) (%)	N/A
Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption) (may be reduced over time) (%)	None
Small account fee1	$15

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment) (%)
Management fees2	0.50
Distribution and service (12b-1) fees	None
Other expenses	0.24
Total annual fund operating expenses2	0.74
Fees waived and/or expenses reimbursed	—3
Total annual fund operating expenses after waiving fees and/or reimbursing expenses2	0.74

¹  If your shares are held in a direct account and the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly (with an annual maximum of $15.00 per account). Direct accounts generally include accounts held in the name of the individual investor on the fund’s books and records.

²  The management fees and total annual fund operating expenses have been restated to reflect current management fees.

³  The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage, taxes, extraordinary expenses and acquired fund fees and expenses) so that total annual operating expenses for Class 1 shares are not expected to exceed total annual operating expenses for Class A shares. This arrangement cannot be terminated prior to December 31, 2014 without the Board of Trustees’ consent.

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)	1 year	3 years	5 years	10 years
Class 1 (with or without redemption at end of period)	76	237	412	919

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

LEGG MASON PARTNERS INCOME TRUST

Prospectus Date

rr_ProspectusDate

Aug. 01, 2012

Supplement [Text Block]

lmpit27_SupplementTextBlock

LEGG MASON PARTNERS INCOME TRUST

SUPPLEMENT DATED NOVEMBER 28, 2012

TO THE SUMMARY PROSPECTUS AND PROSPECTUS,

EACH DATED AUGUST 1, 2012, OF

WESTERN ASSET MORTGAGE BACKED SECURITIES FUND

Effective as of January 1, 2013, the following text replaces any inconsistent information in the section titled “Fees and expenses of the fund” in the fund’s Summary Prospectus and Prospectus:

Shareholder fees (fees paid directly from your investment)
	Class 1
Maximum sales charge (load) imposed on purchases (as a % of offering price) (%)	N/A
Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption) (may be reduced over time) (%)	None
Small account fee1	$15

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment) (%)
Management fees2	0.50
Distribution and service (12b-1) fees	None
Other expenses	0.24
Total annual fund operating expenses2	0.74
Fees waived and/or expenses reimbursed	—3
Total annual fund operating expenses after waiving fees and/or reimbursing expenses2	0.74

¹  If your shares are held in a direct account and the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly (with an annual maximum of $15.00 per account). Direct accounts generally include accounts held in the name of the individual investor on the fund’s books and records.

²  The management fees and total annual fund operating expenses have been restated to reflect current management fees.

³  The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage, taxes, extraordinary expenses and acquired fund fees and expenses) so that total annual operating expenses for Class 1 shares are not expected to exceed total annual operating expenses for Class A shares. This arrangement cannot be terminated prior to December 31, 2014 without the Board of Trustees’ consent.

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)	1 year	3 years	5 years	10 years
Class 1 (with or without redemption at end of period)	76	237	412	919

Western Asset Mortgage Backed Securities Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

lmpit27_SupplementTextBlock

LEGG MASON PARTNERS INCOME TRUST

SUPPLEMENT DATED NOVEMBER 28, 2012

TO THE SUMMARY PROSPECTUS AND PROSPECTUS,

EACH DATED AUGUST 1, 2012, OF

WESTERN ASSET MORTGAGE BACKED SECURITIES FUND

Effective as of January 1, 2013, the following text replaces any inconsistent information in the section titled “Fees and expenses of the fund” in the fund’s Summary Prospectus and Prospectus:

Shareholder fees (fees paid directly from your investment)
	Class 1
Maximum sales charge (load) imposed on purchases (as a % of offering price) (%)	N/A
Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption) (may be reduced over time) (%)	None
Small account fee1	$15

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment) (%)
Management fees2	0.50
Distribution and service (12b-1) fees	None
Other expenses	0.24
Total annual fund operating expenses2	0.74
Fees waived and/or expenses reimbursed	—3
Total annual fund operating expenses after waiving fees and/or reimbursing expenses2	0.74

¹  If your shares are held in a direct account and the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly (with an annual maximum of $15.00 per account). Direct accounts generally include accounts held in the name of the individual investor on the fund’s books and records.

²  The management fees and total annual fund operating expenses have been restated to reflect current management fees.

³  The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage, taxes, extraordinary expenses and acquired fund fees and expenses) so that total annual operating expenses for Class 1 shares are not expected to exceed total annual operating expenses for Class A shares. This arrangement cannot be terminated prior to December 31, 2014 without the Board of Trustees’ consent.

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)	1 year	3 years	5 years	10 years
Class 1 (with or without redemption at end of period)	76	237	412	919

XML

Document and Entity Information	12 Months Ended
	Aug. 01, 2012
Risk/Return:
Document Type	Other
Document Period End Date	Dec. 31, 2011
Registrant Name	LEGG MASON PARTNERS INCOME TRUST
Central Index Key	0000764624
Amendment Flag	false
Document Creation Date	Nov. 28, 2012
Document Effective Date	Nov. 28, 2012
Prospectus Date	Aug. 01, 2012

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	LEGG MASON PARTNERS INCOME TRUST
Prospectus Date	rr_ProspectusDate	Aug. 01, 2012
Document Creation Date	dei_DocumentCreationDate	Nov. 28, 2012