The occurrence and sources of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylate, C4, C6-C8 and C10 sulfonates and C8 sulfonamide) were determined in water, sediment, and biota of the Llobregat River basin (NE Spain). Analytes were extracted by solid phase extraction (SPE) and determined by liquid chromatography triple quadrupole mass spectrometer (LC-QqQ-MS). All samples were contaminated with at least one PFAS, being the most frequently found perfluorobutanoate (PFBA), perfluorooctanoate (PFOA) and perfluorooctane sulfonate (L-PFOS). In general, mean PFAS concentrations measured in sediments (0.01-3.67ngg(-1)) and biota (0.79-431μgkg(-1)) samples were higher than those found in water (0.01-233ngL(-1)). L-PFOS presented very high levels in biota and water, particularly in the Anoia River where a maximum concentration of 2.71μgL(-1) was related to important industrial activities. However, this pollution does not extend down the Llobregat River according to cumulated values. None of the hazard quotients (HQ) calculated indicate potential risk for the different tropic levels considered (algae, Daphnia sp. and fish). According to Maximum Allowable Concentration (MAC) proposed by the European Commission (L-PFOS) and to Provisional Health Advisory (PHA) values (PFOA, L-PFOS) established by the United States Environmental Protection Agency (US EPA), only two water samples exceeded PHA concentration for L-PFOS.