In this study, a simple, fast, and cheap sample preparation procedure for the analysis of three well-known representatives of perfluoroalkyl substances (perfluorooctane sulfonate, perfluorooctanoic acid, and perfluorooctane sulfonamide) was validated in accordance with Commission Decision 2002/657/EC. The method was based on extraction with methanol followed by a dispersive solid phase extraction cleanup step by addition of activated charcoal for fish tissue, fish feed, and milk samples. The novel analytical approach combined with liquid chromatography-tandem mass spectrometry makes it possible to achieve limits of quantification below 1 μg/kg (defined by Commission Recommendation 2010/161/EU). This method provides a high laboratory sample throughput: ten samples in 60 min. The validated procedure was successfully verified in an interlaboratory study.