Electrophilic compounds are ubiquitous in the environment and aquatic life is inevitably affected. Glutathione S-transferases (GSTs) are a class of enzymes that facilitate the detoxification of these electrophiles in phase II metabolism. In this study, cytosolic GSTs were isolated and characterized from striped bass liver (Morone saxitilis). Nanospray liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to elucidate peptide sequences, and the proteins were found to have homology to rho and alpha by searching against the NCBI non-redundant database (nrDB). Catalytic activities of the cytosolic GSTs towards 1-chloro-2,4-dinitrobenzene (CDNB) were determined to be 141+/-34 and 155+/-65nmol/min/mg for males and females, respectively (both n=3). However, sex differences in classes expressed and activity toward CDNB were not statistically significant (p>0.05).