UNITED STATES	OMB APPROVAL
SECURITIES AND EXCHANGE COMMISSION
	OMB Number: 3235-0381
Washington, D.C. 20549	Expires: September 30, 2018
	Estimated average burden
FORM 40-F/A Amendment No. 2	hours per response. . . ...429.93

[Check one]

	¨	REGISTRATION STATEMENT PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934
OR
	x	ANNUAL REPORT PURSUANT TO SECTION 13(a) OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended: December 31, 2017         Commission File Number: 001-38141

Sierra Metals Inc.

(Exact name of Registrant as specified in its charter)

Not Applicable

(Translation of Registrant’s name into English (if applicable))

Canada

(Province or other jurisdiction of incorporation or organization):

1021

(Primary Standard Industrial Classification Code Number (if applicable))

Not Applicable

(I.R.S. Employer Identification Number (if applicable))

79 Wellington Street, West, Ste. 2100, Toronto, Ontario M5K 1H1 (416) 366-7777

(Address and telephone number of Registrant’s principal executive offices)

Cogency Global Inc.

10 East 40th Street, 10th Floor, New York, NY 10016 (800) 221-0102

(Name, address (including zip code) and telephone number (including area code)
of agent for service in the United States)

Securities registered or to be registered pursuant to Section 12(b) of the Act.

Common Shares	NYSE American
Title of each class	Name of each exchange on which registered

Securities registered or to be registered pursuant to Section 12(g) of the Act.

None

Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act.

None

For annual reports, indicate by check mark the information filed with this Form:

Annual information form x         Audited annual financial statements x

Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of the close of the period covered by the annual report.

Common Shares: 163,029,548

Indicate by check mark whether the Registrant by filing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934 (the “Exchange Act”). If “Yes” is marked, indicate the file number assigned to the Registrant in connection with such Rule.

Yes ¨   No x

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Exchange Act during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.

Yes x   No ¨

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 12b-2 of the Exchange Act.

Emerging growth company x

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by checkmark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards† provided pursuant to Section 13(a) of the Exchange Act.

¨

Not applicable

EXPLANATORY NOTE

Sierra Metals Inc. (the “Company” or “we” or “us”) is a Canadian issuer eligible to file its annual report pursuant to Section 13 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), on Form 40-F (“Form 40-F”) pursuant to the multi-jurisdictional disclosure system of the Exchange Act. We filed our Annual Report on Form 40-F for the fiscal year ended December 31, 2017 on March 22, 2018, and we filed Amendment No. 1 to our 2017 Form 40-F on March 26, 2018.

This Amendment No. 2 to our 2017 Form 40-F is being filed solely to furnish the Company's financial statements as of and for the fiscal year ended December 31, 2017 formatted in XBRL (eXtensible Business Reporting Language). In accordance with the policy of the Securities Exchange Commission stated in Release No. 33-9002, we are filing this Amendment No. 2 within the 30-day period following the filing of our Form 40-F available to first-time XBRL filers.

The Company is filing this Amendment No. 2 solely to furnish the information set forth above. Other than as set forth herein, this Amendment No. 2 does not modify or update any disclosures and makes no changes to the Form 40-F.

INDEX TO EXHIBITS

Consents

101

The following financial statements from Sierra Metals Inc. 's Annual Report on Form 40-F for the fiscal year ended December 31, 2017, formatted in XBRL (eXtensible Business Reporting Language): 101.INS XBRL Instance Document 101.SCH XBRL Taxonomy Extension Scheme Document 101.CAL XBRL Taxonomy Calculation Linkbase Document 101.DEF XBRL Extension Definition Linkbase Document 101.LAB XBRL Taxonomy Extension Linkbase Document

SIGNATURES

Pursuant to the requirements of the Exchange Act, the Registrant certifies that it meets all of the requirements for filing this Form 40-F and has duly caused this amendment to our annual report to be signed on its behalf by the undersigned, thereto duly authorized.

	SIERRA METALS INC.
	By:	/s/ Igor Gonzales
	Name:	Igor Gonzales
	Title:	President and Chief Executive Officer
Date: April 2, 2018