CERTIFICATION
                             Pursuant to Section 906
                        of the Sarbanes-Oxley Act of 2002


         The undersigned, the Chief Executive Officer of SEI Institutional
Managed Trust (the "Fund"), with respect to the Form N-CSR for the period ended
May 31, 2003 as filed with the Securities and Exchange Commission, pursuant to
18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley
Act of 2002, hereby certifies that, to the best of my knowledge:

         1. such Form N-CSR 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-CSR fairly presents, in all
material respects, the financial condition and results of operations of the
Fund.


Dated: November 26, 2003


                                              /s/ Edward D. Loughlin
                                              ----------------------
                                              Edward D. Loughlin




A signed original of this written statement required by Section 906, or other
document authenticating, acknowledging, or otherwise adopting the signature that
appears in typed form within the electronic version of this written statement
required by Section 906, has been provided to SEI Institutional Investments
Trust and will be retained by SEI Institutional Investments Trust and furnished
to the Securities and Exchange Commission or its staff upon request.