CERTIFICATION Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 The undersigned, President and Chief Executive Officer of SEI Institutional Managed Trust (the "Trust"), with respect to the Trust's Form N-CSRS for the period ended March 31, 2009 as filed with the Securities and Exchange Commission, hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge: 1. such Form N-CSRS 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 such Form N-CSRS fairly presents, in all material respects, the financial condition and results of operations of the Trust. Dated: May 29, 2009 /s/ Robert A. Nesher ---------------------------------------- Robert A. Nesher CERTIFICATION Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 The undersigned, the Controller & CFO of SEI Institutional Managed Trust (the "Trust"), with respect to the Trust's Form N-CSRS for the period ended March 31, 2009 as filed with the Securities and Exchange Commission, hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge: 1. such Form N-CSRS 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 such Form N-CSRS fairly presents, in all material respects, the financial condition and results of operations of the Trust. Dated: May 29 2009 /s/ Stephen F. Panner ---------------------------------------- Stephen F. Panner