Objective: To determine the toxic effect of diethanolamine on testicular steroidogenesis and its possible amelioration by curcumin in mice. Methods: Adult Swiss strain male albino mice were orally administered with diethanolamine (110, 165 and 330 mg/kg body weight) for 45 days. In another set of experiment, male albino mice were orally administered with curcumin (10, 25 and 50 mg/kg body weight) along with diethanolamine (330 mg/kg body weight) for 45 days. On completion of treatment, animals were humanely sacrificed, testis dissected out, blotted free of blood and used for biochemical analysis. The obtained serum samples were analyzed for serum testosterone level. Results: Diethanolamine caused significant (P<0.05), dose-dependent reduction in total lipid and cholesterol contents, activities of 3β- and 17β- hydroxysteroid dehydrogenases in testis as well as significant reduction in serum testosterone level. However, co-treatment of curcumin along with diethanolamine caused significant (P<0.05) dose-dependent amelioration in diethanolamine-induced changes in total lipid and cholesterol contents, activities of 3β- and 17β-hydroxysteroid dehydrogenases and serum testosterone levels. Conclusions: The results of the present study showed that curcumin significantly ameliorates diethanolamine reduced testicular steroidogenesis.