Fusarium oxysporum f. sp. fabae (Schlecht) (FO) was isolated from diseased faba bean roots collected from different localities at Assiut governorate. The antagonistic capability of Trichoderma spp. isolates against linear growth of FO isolate was tested and all Trichoderma spp. isolates gave positive reaction of antagonism to the pathogen isolate in vitro. In greenhouse and field experiments, all applied treatments protected faba bean seedlings against FO. The most effective treatments were T. harzianum (Tzl) followed by T. viride (Tl) and T. harzianum (Tl5). Soil treatments by Trichoderma spp. isolates reduced the disease index. All treatments significantly increased cellulose, pectin and lignin contents in treated plants compared with untreated plants. The highest increase of pectin was obtained with T. harzianum (Tzl).