SHIP LOGO VANGUARD(R) P.O. BOX 2600 VALLEY FORGE, PA 19482-2600 610-669-1538 Judy_L_Gaines@vanguard.com September 6, 2006 Christian Sandoe, Esq. Division of Investment Management U.S. Securities and Exchange Commission via electronic filing 450 Fifth Street, N.W., Fifth Floor Washington, D.C. 20549 RE: Vanguard Quantitative Funds Dear Mr. Sandoe, The following responds to your comments of August 29, 2006 on the post-effective amendment of the registration statement of the above-referenced registrant. You commented on Post-Effective Amendment No. 27 that was filed on July 5, 2006. Comment 1: Prospectus - Primary Investment Strategies - ------------------------------------------------------------ Comment: Include a reference to any market capitalization strategy employed by the Fund, and include the market capitalization as of a recent date. Response: The Fund does not have a primary investment strategy of investing in any particular market capitalization, so we do not plan to include anything in the Item 2 disclosure. However, we will include the market capitalization range of the Fund's target index as of a recent date in our Item 4 disclosure. Comment 2: Prospectus - Performance/Risk Information - ----------------------------------------------------------- Comment: Revise the second sentence of footnote 1 so it is clear whether the Fund's Portfolio Manager served in this capacity for both the Fund and the collective trust that preceded it. Response: We will make the requested edit so it is clear that the same PM has managed the Fund's assets dating back to the inception date of the collective trust that preceded the Fund. Comment 3: Prospectus - Plain Talk About the Fund's Portfolio Manager - ---------------------------------------------------------------------------- Comment: Please clarify whether the PM has managed the Fund and the collective trust since the inception of each. Christian Sandoe, Esq. September 6, 2006 Page 2 Response: The PM has managed both the collective trust and the Fund since inception so we will modify our disclosure to make this more clear. Comment 4: Tandy Requirements - ------------------------------------ As required by the SEC, the Fund acknowledges that: o The Fund is responsible for the adequacy and accuracy of the disclosure in the filing. o Staff comments or changes in response to staff comments in the filings reviewed by the staff do not foreclose the Commission from taking any action with respect to the filing. o The Fund may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States. Please contact me at (610) 669-1538 with any questions or comments regarding the above responses. Thank you. Sincerely, Judith L. Gaines Associate Counsel Securities Regulation, Legal Department