Abstract: The genotoxic potential of blitox (fungicide) was investigated by using chromosome aberration in Allium cepa root tip cells. Allium cepa roots were treated with 2g/lt., 3g/lt. and 4g/lt. concentrations of blitox and distilled water as control at 4 hours, 8 hours and 12 hours duration. The results indicated that blitox significantly increased the genetical abnormalities at all concentrations and treatment periods when compared with their controls and this increase was dose-dependent for the 4, 8 and 12 hours treatments. On the other hand, blitox significantly decreased the mitotic index (MI) in all treatments when compared with their controls. This study indicates that blitox decreased the mitotic index and produced clastogenic and aneugenic types of abnormalities in Allium cepa root tip cells.