Abstract: Onion (Allium cepa L.) is one of the most important vegetable cum condiment crop of family Alliaceae, grown in all the parts of India. Onion bulbs and green onions both are rich in minerals, proteins and ascorbic acid. Onion is used throughout the year in the form of salad or condiment or for cooking with other vegetables. Onion is also used for making pickles in vinegar or brine. Its use in soups and souce is very common. Onion has several medicinal uses, its use in the case of sun strokes is known world over. Basal rot of onion caused by Fusarium oxysporum is a wide spread disease observed in nurseries as well as in field in the vicinity of Jobner, which causes losses at all the stages of crop growth right from germination to till harvest and also in storage. The efficacy of different fungicide, Benlate, Bavistin, Blitox, Captan and Thiram of different concentrations (50, 100, 200 and 300 ppm) and organic amendments neem cake, mustard cake, groundnut cake, vermicompost and goat and sheep manure of different concentrations (10, 20, 30%). Benlate was found most effective with complete inhibition of mycelial growth of the fungus at 200 and 300 ppm concentrations followed by Bavistin and Blitox. In organic amendements neem cake was found most effective in inhibiting the mycelial growth of Fusarium oxysporum and it was followed by mustasrd cake.