Rice blast caused by Magnaporthe oryzae is one of the most devastating diseases of rice and account for yield loss up to 65% in susceptible cultivars of rice. Trichoderma spp. has emerged as a potential biological control agent against many plant pathogenic fungi and also improved plant growth parameters. An experiment was carried out to evaluate the efficacy of seed treatment with different Trichoderma spp. isolate against leaf blast in four rice varieties; Swarna, IR–64, Samba Mahsuri, and Sahbhagi Dhan under upland rice conditions at Almora and Hazaribag. Trichoderma spp. (isolate Th–3) treated seed of SambaMahsuri (57%) showed maximum plant height percentage followed by Tv–12 isolate with Samba Mahsuri (44%) as compared to control. It also increases root length (51–93%), total number of leaves (6.–60.%), tillers (3.–41%), panicles (4–39%), flag leaf

length (2.–30%) and panicle length (5–32%) as compared to untreated control. The Trichoderma treated seed showed low disease intensity at Almora and Hazaribag as compared to untreated seed. The present study showed that it reduces the disease intensity by 10–25%, suggested that Trichoderma spp. may be used as bio–inoculants for biological control of rice blast disease.