[Logo] PIONEER Investments(R)





March 6, 2012



VIA ELECTRONIC TRANSMISSION
---------------------------

Securities and Exchange Commission
Division of Investment Management
100 F Street, NE
Washington, DC  20549

Re:     Pioneer Mid Cap Value Fund (the "Fund")
        File Nos. 033-34801 and 811-06106
        CIK No. 0000863334

Ladies and Gentlemen:

Pursuant to Rule 497(j) under the Securities Act of 1933, as amended, I certify
that the form of prospectus for the Fund, which would have been filed under
paragraph (c) of Rule 497, does not differ from that contained in Post-
Effective Amendment No. 36 to the Fund's registration statement on Form N-1A,
filed electronically on February 28, 2012 (Accession No. 0000863334-12-000002).

If you have any questions concerning the foregoing certification, please
contact me at (617) 422-4703.

Very truly yours,



/s/ Kathleen H. Alexander
-------------------------
    Kathleen H. Alexander
    Legal Product Manager


cc:     Christopher J. Kelley, Esq.
        Toby R. Serkin, Esq.



Pioneer Investment Management, Inc.
60 State Street
Boston, MA  02109-1820




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