Abstract Oil, phtalates and biotoxin pollution on mussels were investigated at the entrance and exit of Dardanelles between June 2001 and May 2002. The max. oil pollution was found in May 2002 in the Çanakkale and Gelibolu samples as 28.26 µg/g and 17.'26 µg/g (wet weight), respectively. The detected of oil compounds were aliphatic group as C1O-C22 and aromatic group as phenol, naphthalene, anthracene, phenanthrene, indol, thiophene, dibenzothiophene derivatives. Phthalates derivatives, dibutyl, diisobutyl phthalate, DEHP (bisethyl hexyl phthalate) were identified by GC/MS analyses. Biotoxine analysis was made by bioassay; PSP and DSP mouse tests were found positive. This is first record in Turkey.