<Page> Exhibit 99.906CERT CERTIFICATION PURSUANT TO RULE 30a-2(b) UNDER THE INVESTMENT COMPANY ACT OF 1940 This certification is provided pursuant to Rule 30a-2(b) under the Investment Company Act of 1940, and accompanies the report on Form N-CSR furnished to the Securities and Exchange Commission on the date hereof of the JPMorgan Fleming Asia Equity Fund, JPMorgan Fleming Intrepid European Fund, JPMorgan Fleming International Growth Fund, JPMorgan Fleming Japan Fund and JPMorgan Fleming Tax Aware International Opportunities Fund (the "Funds"), each a series of J.P. Morgan Mutual Fund Group. I, George C.W. Gatch, certify that: 1. The Form N-CSR fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as applicable; and 2. The information contained in the Form N-CSR fairly presents, in all material respects, the financial condition and results of the operations of the Funds. /s/ George C.W. Gatch - ----------------------- George C.W. Gatch President June 23, 2004 - ----------------------- Date This certificate is furnished pursuant to the requirements of Form N-CSR and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, or otherwise subject to the liability of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Exchange Act of 1934. <Page> CERTIFICATION PURSUANT TO RULE 30a-2(b) UNDER THE INVESTMENT COMPANY ACT OF 1940 This certification is provided pursuant to Rule 30a-2(b) under the Investment Company Act of 1940, and accompanies the report on Form N-CSR furnished to the Securities and Exchange Commission on the date hereof of the JPMorgan Fleming Asia Equity Fund, JPMorgan Fleming Intrepid European Fund, JPMorgan Fleming International Growth Fund, JPMorgan Fleming Japan Fund and JPMorgan Fleming Tax Aware International Opportunities Fund (the "Funds"), each a series of J.P. Morgan Mutual Fund Group. I, Patricia A. Maleski, certify that: 1. The Form N-CSR fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as applicable; and 3. The information contained in the Form N-CSR fairly presents, in all material respects, the financial condition and results of the operations of the Funds. /s/ Patricia A. Maleski - ------------------------- Patricia A. Maleski Treasurer June 22, 2004 - ------------------------- Date This certificate is furnished pursuant to the requirements of Form N-CSR and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, or otherwise subject to the liability of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Exchange Act of 1934.