Exhibit (b)

                            CDC Nvest Funds Trust III
                            Section 906 Certification

     In connection with the report on Form N-CSR for the period ended June 30,
2004 for the Registrant (the "Report"), the undersigned each hereby certifies to
the best of his knowledge, pursuant to section 906 of the Sarbanes-Oxley Act of
2002, that:

     1. the Report complies with the requirements of Section 13(a) or 15(d) of
the Securities and Exchange Act of 1934, as applicable; and

     2. the information contained in the Report fairly presents, in all material
respects, the financial condition and results of operations of the Registrant.


By:                                          By:
President & Chief Executive Officer          Treasurer
CDC Nvest Funds Trust III                    CDC Nvest Funds Trust III

/s/ John T. Hailer                           /s/ Nicholas H. Palmerino
- -----------------------------------          -----------------------------------
John T. Hailer                               Nicholas H. Palmerino

Date: August 20, 2004                        Date: August 20, 2004

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 the CDC Nvest Funds Trust II and
will be retained by the CDC Nvest Funds Trust II and furnished to the Securities
and Exchange Commission or its staff upon request.