The protective effect of Vitamin E and selenium was studied for the possibility of decreasing the chromosome aberrations (CA), micronuclei (MN) and sister chromatid exchanges (SCE) induced by carbon tetrachloride (CCl4) in ovine peripheral lymphocytes cultured in vitro. The cultures of lymphocytes from two healthy lambs were treated with carbon tetrachloride at concentrations of 2, 4, 8, and 16μg/ml for the last 48h of cultivation and subsequently with the same doses of CCl4 and Vitamin E and selenium. A possible metabolic modification in carbon tetrachloride genotoxicity was detected with the application of S9 fraction for 2h. No positive clastogenic effect of CCl4, and subsequently no protective effect of either antioxidant was obtained in the CA assay. In the MN assay for 48h, an increase and, respectively, a decrease in the frequency of MN was found in cultures treated with CCl4 alone and in cultures treated concurrently with CCl4, Vitamin E and selenium at concentrations of 8 and 16μg/ml (P<0.001 and P<0.01). High statistical significance was achieved in SCE assay after the treatment of ovine peripheral lymphocytes with CCl4 at all concentrations tested (P<0.001), except the lowest dose. A significant decrease in SCEs was obtained in cultures treated simultaneously with CCl4, Vitamin E and selenium (P<0.001). The highest dose (16μg/ml) was also shown to improve the cell-cycle kinetics in comparison with corresponding unprotected dose (P<0.01). Insufficient confirmation of the genotoxicity of CCl4 and the protective effect of the antioxidants, respectively were seen in cultures with metabolic activation.