Widespread contamination of the environment due to increased and frequently indiscriminate usage of insecticides during the last two decades has aroused much concern over the possibility of their radiominetic effect. Evidence accumulating over the years emphasized the indisputable link between certain insecticides, chromosomal damage and possibility of gene mutation. There is a wide variety of insecticides, among which the carbamates. Their chemical relationship to ethyl carbamate makes them worthy of study for their possible deleterious effect on biological system. The main object of the present study is to evaluate the mutagenic effect of a carbamate insecticide" Aldicarb" alone and in combination of vitamin C as an antioxidant agent to decrease their mutagenicity. Male albino rats were tested orally for 48 hours , two doses of aldicarb were used in absence and in the presence of viamin C (1/4 and 1/10) LD50. The obtained data showed highly significant increase in the micronucleus (PCEM) and in chromosomal aberrations in rat bone marrow cells at the two doses of aldicarb compared to control group. (P< 0.0001). The frequency of chromosomal aberrations and micronucleus decreased in rats treated with aldicarb and vitamin C than in aldicarb treated group. From these results we concluded that cytogenetic effect of aldicarb might be decreased by the usage of vitamin as an antioxidant agent.