ONION (Allium cepa L.) is a very important vegetable crop in Egypt and all over the world. White rot is a serious disease of Allium spp. caused by the soil-borne fungus Sclerotium cepivorum. In this study, three Trichoderma species and one vegan compost, alone or in combinations with the fungicide folicur were tested for their ability to inhibit mycelial growth of S. cepivorum. The results of the laboratory experiment showed that T. hamatum is the most effective as it recorded the highest inhibition (100% over growth) of the mycelial growth of the fungus followed by T. viride (64.6%) and T. harzianum (63.5%). The results indicated also that the compost tea caused inhibition of the fungus by 57.1%. In the pots experiment, folicur showed the highest efficiency (75.0%) to reduce the disease incidence, followed by T. harzianum combined with T. hamatum and folicur combined with T. viride and T. hamatumthat had 70.8% efficiency.