Many countries have had to deal with the death of wild animals and domestic livestock due to toxic microalgal blooms in both marine and fresh water. Poisoning in humans has been associated with the direct consumption of shellfish, fish, or toxin-contaminated water. The foods most frequently involved in episodes of human poisoning are represented by bivalve molluscs. In accordance with current European regulations, we propose a quick, selective, sensitive, and accurate analytical method for the determination of lipophilic marine biotoxins in bivalve molluscs using an LC-MS/MS method.