EXHIBIT 23 Consent of Independent Registered Public Accounting Firm We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (File No. 333-18979), Form S-8 (File No. 33-38488), Form S-8 (File No. 33-78868), Form S-8 (File No. 33-89214), Form S-8 (File No. 33-65443), Form S-8 (File No. 333-74825), Form S-8 (File No. 333-75312), and Form S-3 (file No. 333-109139) of Meridian Bioscience, Inc. of our report dated November 12, 2004 relating to the financial statements and financial statement schedule, which appears in this Form 10-K. /s/ PricewaterhouseCoopers LLP Cincinnati, Ohio December 13, 2004