Cultured cells of the toxic Alexandrium tamarense were fed to four mussel species, Mytilus coruscus, M. edulis, M. galloprovincialis and Septifer vulgatus, to examine the interspecies and interlocality differences in the ability to accumulate paralytic shellfish poisoning (PSP) toxins. Toxin content of A. tamarense cells varied during culture period. In contrast, toxin composition in the cell (C1,2, GTX1-4 and neoSTX) was constantly stable. In feeding experiment, the four mussel species collected from Geoje intoxicated after uptake of A. tamarense. Toxin content ($average{pm}SD;{mu}g$ STXeq/100 g) of M. coruscus, M. edulis, M. galloprovincialis and Septifer vulgatus were $1,660{pm}79,;3,914{pm}2,242,;5,626{pm}1,620;and;958{pm}163$, respectively. Toxin profiles included C1,2, GTX1,4 and neoSTX as the major components, and dcGTX2,3, GTX2,3, neoSTX and STX as the minor ones. Toxin accumulation of three mussel species collected from Pohang, Geoje and Anmyon-do showed interspecies and interlocality differences. Toxin content ($average{pm}SD;{mu}g$ STXeq/100 g) were $91{pm}4,;151{pm}14,;39{pm}3$ in M coruscus, $189{pm}1,;231{pm}11,;206{pm}15$ in M edu/is and $214{pm}28,;326{pm}30,;291{pm}26$ in M. galloprovincialis in order of Anmyon-do, Geoje and Pohang.