UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

Amendment No. 1 to

FORM 10-Q

(Mark One)

For the quarterly period ended June 30, 2012

OR

For the transition period from ________ to _________

Commission File Number 000-49636

VIKING SYSTEMS, INC.

(Exact name of registrant as specified in its charter)

134 Flanders Road, Westborough, MA 01581

 (Address of principal executive offices) (Zip Code)

(508) 366-3668

(Registrant’s telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 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 has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).   Yes x No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).   Yes ¨ No x

The registrant had 72,554,620 shares of common stock, $0.001 par value per share, issued and outstanding as of August 13, 2012.

EXPLANATORY NOTE

This Amendment No. 1 to the Quarterly Report on Form 10-Q is being filed solely to furnish the Interactive Data files as Exhibit 101, in accordance with Rule 405 of Regulation S-T. No other changes have been made to the Form 10-Q, as originally filed on August 20, 2012.

Item 6. Exhibits

* Pursuant to Rule 406T of Regulation S-T, the interactive data files on Exhibit 101 hereto are deemed not filed or part of a registration statement or prospectus for purposes of Sections 11 or 12 of the Securities Act of 1933, as amended, are deemed not filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, and otherwise are not subject to liability under those sections.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has caused this report to be signed on its behalf by the undersigned thereunto duly authorized.