Profenofos (EC(50)) is a persistent and toxic organophosphorus insecticide. Animals get exposed to profenofos via food and water. The present study was designed to explore the genotoxic effect of profenofos in the marine fish. The ubiquitously occurring marine fish, Therapon jarbua, was exposed to profenofos and its effect on DNA was measured using comet (single-cell gel electrophoresis) assay. DNA damage were scored using mean percentage of tail length and compared with the comet classes' viz., 0, 1, 2, 3, and 4. In the first three doses, the (21.5, 43.0 and 86.0 µg L(-1)) comets were observed, of which the mean tail length differed significantly (p