The isolation of microorganisms from rhizosphere of healthy wheat plants was carried out to select the most antagonistic one to be used in biological control of root-rot disease of wheat caused by Fusari­urn graminearum, Helminthosporium sativum and Rhizoctonia solani. Tri­choderma harzainum, T. hamatum, Streptornyces griseus and Bacillus subtilis were the most frequently isolated microorganisms. According to in vitro testing, T. harzianum gave the highest significnt reduction in my­celia! gowth of the pathogenic fungi followed by T. hamatum. Antagonis­tic fungi (T. harzainum and T. hamatum) completely inhibited sclerotial formation in R solani. The antagonism between the pathogen and the bioagent could be affected by the type of media. Slide techinque was used to study the mode of action of bioagents on pathogenic fungi. T. harzianum caused malformation in the mycelium of pathogenic fungi and grew over the host mycelium followed by more close contact interaction and invasion. B. subtilis also caused malformation and decaying for path­ogenic mycelia. in viva test was carried Out to evaluate the efficacy of adding dif­ferent bioagents in different forms, dates and rates to the soil infested with pathogenic fungi. Adding the antagonistic fungi as powder gave better result in controlling root-rot disease. While adding bacteria and streptomyces as suspenison was the most effective. One week before planting time was the most suitable date for adding bioagents to the in­fested soil to control root-rot disease. While 5 and 10 g/Kg soil were the most effective rate of bioagents which led to reduction in disease inci­dence of wheat root-rot.