Abstract: The Fungicide Captan was screened in Allium cepa multiple assay test for mutagenic activity. Actively dividing root tips were treated with four different concectrations 5, 10, 20 and 40 ppm of the fungicide for 1, 3, 6, 12 and 24 hours. Almost all trearments exerted a mitodepressive action indicating that the fungicide has an immediate effect on cell division . It was noted that the fungicide exerts a clastogenic effect on chromosomes. Mitotic aberrations observed included stickiness of chromosomes at prophase, metaphase, bridging at anaphase and bi and tri nucleated cells. Such aberrations are important as they may have evolutionary significance.