The effect of triclabendazole, which is a benzimidazole anthelmintic, on the survival rate and developmental time in different stages of greater wax moth Galleria mellonella (L.) was investigated by rearing the larvae on the artificial diets. Triclabendazole was incorporated into diets at concentrations of 0.001, 0.01 or 0.1%. G. mellonella larvae was reared from first instar larvae to adult emergence on the artificial diets with different concentrations of triclabendazole. The survival rate in seventh instar (7th-instar) and adult stage were significantly lower at low concentrations of this anthelmintic agent (0.001 and 0.01 g per 100 g of diet) than the control, while there were no differences on pupation in comparison to control diet. However, the pupation and adult emergence were significantly lower at the highest dietary concentration of triclabendazole than control group but there were no differences on survival of 7th-instar larvae. The highest concentration of the anthelmintic agent (0.1 g/100 g diet) decreased pupation from 81.6 +/- 4.32% to 43.3 +/- 7.45%, adult emergence rate from 73.3 +/- 2.36 to 13.3 +/- 2.36. Triclabendazole at the highest concentration prolonged developmental time to 7th larval stage by 3.8 days reaching total 22.8 +/- 1.54 days. This diet containing 0.1% of triclabendazole significantly prolonged pupal developmental time from 24.6 +/- 1.24 days to 28.4 +/- 1.24 days, adult developmental time from 35.3 +/- 1.27 days to 42.0 +/- 1.62 days. This study is of importance in appreciation for usage of antihelmintic with different structure and mode of actions in the management of pest insects to reduce damage to environment and nontarget organisms.