Biological control of plant diseases is a safer and more cost-effective technology for controlling serious diseases, besides facilitating and improvement plant development, yield and production. The causative organisms of root-rot and damping-off diseases were isolated from diseased bean roots, these isolates were identified as Pythium ultimum 4413AUMC and Rhizoctonia solani 6590AUMC. Colony characteristics, growth, mycelium structure, conidiophores, phialides and conidia were used to identify Trichoderma species isolated from rhizosphere soils around healthy bean roots collected from 23 locations in Egypt. Trichoderma spp. successfully reduced P. ultimum mycelial growth, with eight isolates showing total overgrowth on P. ultimum. The results demonstrated that all the isolated Trichoderma spp. severely affected R. solani radial growth, with nine isolates showed full overgrowth. The Trichoderma isolate T5 caused total overgrowth (100 percent inhibition) against phytopathogenic fungi and was chosen for species identification as Trichoderma koningii. The examination of fungus filtrate showed that T. koningii produces the enzyme chitinase which hydrolyzes chitin in fungal infections (0.98 u.mg^-1 protein) and a large amount of protease enzyme (6.34 u/mg protein). In a scanning electron microscope from interaction zone, the mycelial samples of R. solani and T. koningii from a dual culture, indicated the mycoparasitic nature of T. koningii on R. solani. T. koningii was found to be a cost-effective bioagent for suppressing the phytopathogenic microorganisms, P. ultimum and R. solani.