The protective effect of melatonin against doxorubicin induced testicular toxicity was investigated in male rats. Melatonin was administered orally to rats at a dose of 6 mg/kg daily for 28 days along with doxorubicin. Doxorubicin was administered intraperitoneally to the animals at a dose of 3mg/kg once a week for 5 weeks (a total of 15mg/kg) on day 1, 7, 14, 21, 28. Treatment with doxorubicin alone caused decrease in body weight, sperm count and serum testosterone and increase in serum levels of lactate dehydrogenase (LDH), creatine phosphokinase (CK), and glutamic oxaloacetate transaminase (GOT). However, the combined treatment of melatonin with doxorubicin restored the body weight, sperm count and serum markers to normal. It was observed that administration of melatonin along with doxorubicin caused significant increase in superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH), membrane bound enzymes like Na+K+ATPase, Ca2+ATPase, Mg2+ATPase and decrease in lipid peroxidation (LP) in testes, indicating protection afforded by melatonin administration. These findings indicate that melatonin might be having protective effect against doxorubicin induced testicular toxicity.