3M (MMM) 10-K 2004 FY Annual report

EXHIBIT 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statements of 3M Company on Form S-8 (Registration Nos. 33-14791, 33-49842, 33-58767, 333-26957, 333-30689, 333-30691, 333-44760, 333-44692, 333-73192, 333-101727, 333-101751 and 333-109282), and Form S-3 (Registration Nos. 33-48089, 333-42660, 333-98163, 333-109211 and 333-112563), of our report dated February 14, 2005, relating to the consolidated financial statements, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, which appears in this Annual Report on Form 10-K.

/s/ PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP

Minneapolis, Minnesota

February 23, 2005

1