The present study was designed to evaluate the genotoxicity of albendazole (ABZ) in mice using the micronucleus test. Mice were treated by gavage with 500, 1,000, and 1,500 mg of ABZ kg(-1) b.w., which corresponds to 1/6, 1/3, and 1/2 of the oral LD50 of ABZ. In the second part of the study, the possible protective role of vitamin C (vit. C) was investigated against the genotoxic effect of ABZ. The mice received 200 mg of vit C kg(-1) b.w. simutaneously with ABZ. Bone marrow samples were taken 48 h after the treatment. ABZ induced a statistically significant increase (P<0.001) in the percentage of micronucleaoted polychromatic erythrocytes (MNPCE) in the 1,000 and 1,500 mg of ABZ kg(-1) b.w. treatment groups when compared with the negative control. On the other hand, the percentage of induced MNPCE was reduced at various levels in all ABZ treated groups simultaneously treated with an oral administration of vit. C. There were no statistically significant differences in the MNPCE frequency of these groups. The results of the study indicated that ABZ is a potential genotoxic agent, and that no protective effects of vit. C were observed against the genotoxicity of ABZ.