Constar International (CNSTQ) 10-Q 2010 Q1 Quarterly report

Exhibit 32.2

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350
AS ADOPTED PURSUANT TO SECTION 906 OF
THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Constar International Inc. (the “Company”) on Form 10-Q for the period ending March 31, 2010, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Mark Borseth, Executive Vice President and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ J. Mark BorsethJ. Mark Borseth

Executive Vice President and Chief Financial Officer

May 12, 2010