EX-99.906CERT CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT I, Carter E. Anthony, President and Principal Executive Officer of RMK Strategic Income Fund, Inc. (the "Fund"), certify that: 1. The Form N-CSR of the Fund (the "Report") fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and 2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Fund. Date: May 27, 2005 /s/ Carter E. Anthony --------------- --------------------- Carter E. Anthony, President and Principal Executive Officer CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT I, Joseph C. Weller, Treasurer and Principal Financial Officer of RMK Strategic Income Fund, Inc. (the "Fund"), certify that: 1. The Form N-CSR of the Fund (the "Report") fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and 2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Fund. Date: May 27, 2005 /s/ Joseph C. Weller --------------- -------------------- Joseph C. Weller, Treasurer and Principal Financial Officer