For centuries, plants have been used in traditional medicine and there has been recent interest in the chemopreventive properties of compounds derived from plants. In the present study, we investigated the effects of extracts of Acacia nilotica leaves on the genotoxicity of arsinic .             Arsenic contamination in groundwater a global human health hazard .There is no effective remedial action of chronic arsenicsis. However, a well-nourished diet can modulate the onset of adverse health effects and delayed the effect of arsenic in drinking water. In the present work, genotoxic effects were induced by sodium arsenate through oral administration,and the protective effect of Acacia nilotica was studied. Chromosomal aberrations were more pronounced in sodium arsenate treated mice, while supplementation of Acacia nilotica with sodium arsenate reduced the incidence of the aberrations. The mean of DNA fragmentation induced by sodium arsenate was highly significant increase. However, the administration of Acacia nilotica significantly decreased DNA fragmentation induced by sodium arsenate. The mean number of sperms, were decreased significantly after treatment with sodium arsenate, while administration of Acacia nilotica increased the number of sperm in mice treated with sodium arsenate, and also decreased the percentage of sperm abnormalities induced by sodium arsenate.          The outcome of study showed that Acacia nilotica has the efficiency to encounter the genotoxic effects induced by arsenic.