The study assessed the cytotoxic effect of two heavy metals, Cadmium and nickel in Allium cepa, L and antigenotoxic potential of Moringa oleifera, Lam. leaves extract against these heavy metals. Bulbs of A. cepa were exposed to20, 40, 60, 80 and 100 ppm of Cadmium and Nickel supplied in the form of CdCl2 and NiCl2. A gradual decrease in the germination percentage, mitotic index and increase in the frequency of aberration were observed with increasing concentrations of the heavy metals. Chromosomal stickiness and c- mitosis were found to be common aberrations due to metal exposure. Of the two heavy metals used in the study, Cd was found to be more toxic to A.cepa compared to Ni. The investigation also establishes the antigen toxic potential of M.oleifera leaves, as there was an increase in germination percentage and mitotic index and a decrease in the frequency of aberrations in both the metal treated cells on exposure to 0.5% aqueous extract of M. oleifera leaves. The recovery action was more pronounced in Cd exposed cells compared to Ni.