The effects of profenofos on rat testis and liver was evaluated when applied for 10 weeks, either alone or mixed with vitamin C.  Sperm counts, motility, morphology, reduced glutathione, catalase, superoxide dismutase, malodialdehyde, testosterone level, RT-PCR SSCP of gene P53 were studies. Significant decrease in sperm motility and survival were observed in treated rats. Serum testosterone decreased after exposure for 5 and 10 weeks. MDA content in serum, liver and testis showed significant increase. The activity of hepatic SOD increased, while CAT activity was not changed after 5 weeks exposure. After 10 weeks exposure, the activity of SOD and CAT in both liver and testis, were lower than the control group. At the end of the two exposure periods, GSH levels in both tissues were significantly higher in profenofos treated groups compared to control group.  Results of 10 weeks exposure using RT- PCR SSCP analysis suggested profenofos induction of genotoxicity.