CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the
undersigned officers of Sit Mutual Funds, Inc., do hereby certify, to such
officer's knowledge, that the report on Form N-CSR of Sit Mutual Funds, Inc. for
the period ended June 30, 2004 fully complies with the requirements of Section
13(a) or 15(d) of the Securities Exchange Act of 1934 and information contained
in the Form N-CSR fairly presents, in all material respects, the financial
condition and results of operations of Sit Mutual Funds, Inc. for the periods
presented in the report.

/s/ Eugene C. Sit                      /s/ Paul E. Rasmussen
- -------------------------------        -------------------------------------
Eugene C. Sit                          Paul E. Rasmussen
Chairman                               VP Treasurer
Sit Mutual Funds, Inc.                 Sit Mutual Funds, Inc.

Dated: August 30, 2004
       ---------------

A signed original of this written statement required by Section 906 has been
provided by Sit Mutual Funds, Inc. and will be retained by Sit Mutual Funds,
Inc. and furnished to the SEC or its staff upon request.





CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the
undersigned officers of Sit Large Cap Growth Fund, Inc., do hereby certify, to
such officer's knowledge, that the report on Form N-CSR of Sit Large Cap Growth
Fund, Inc. for the period ended June 30, 2004 fully complies with the
requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934
and information contained in the Form N-CSR fairly presents, in all material
respects, the financial condition and results of operations of Sit Large Cap
Growth Fund, Inc. for the periods presented in the report.

/s/ Eugene C. Sit                      /s/ Paul E. Rasmussen
- -------------------------------        -------------------------------------
Eugene C. Sit                          Paul E. Rasmussen
Chairman                               VP Treasurer
Sit Large Cap Growth Fund, Inc.        Sit Large Cap Growth Fund, Inc.

Dated: August 30, 2004
       ---------------

A signed original of this written statement required by Section 906 has been
provided by Sit Mutual Funds, Inc. and will be retained by Sit Mutual Funds,
Inc. and furnished to the SEC or its staff upon request.





CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the
undersigned officers of Sit Mid Cap Growth Fund, Inc., do hereby certify, to
such officer's knowledge, that the report on Form N-CSR of Sit Mid Cap Growth
Fund, Inc. for the period ended June 30, 2004 fully complies with the
requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934
and information contained in the Form N-CSR fairly presents, in all material
respects, the financial condition and results of operations of Sit Mid Cap
Growth Fund, Inc. for the periods presented in the report.

/s/ Eugene C. Sit                      /s/ Paul E. Rasmussen
- -------------------------------        -------------------------------------
Eugene C. Sit                          Paul E. Rasmussen
Chairman                               VP Treasurer
Sit Mid Cap Growth Fund, Inc.          Sit Mid Cap Growth Fund, Inc.

Dated: August 30, 2004
       ---------------

A signed original of this written statement required by Section 906 has been
provided by Sit Mutual Funds, Inc. and will be retained by Sit Mutual Funds,
Inc. and furnished to the SEC or its staff upon request.