Abstract: Stem and root rot complex disease of groundnut is a devastating disease caused by Sclerotium rolfsii and Macrophomina phaseolina. To avoid extensive use of pesticides, biological formulation developed from Trichoderma harzianum (Th3) was used as an environment friendly option. In the dual culture method, T. harzianum Th3 showed around 62% inhibition against S. rolfsii and 71.9% inhibition of M. phaseolina. Seed treatment, soil application and drenching with T. harzianum Th3 showed minimum disease incidence of 21.6% in Banswara and 12.6% in Jhabua districts. Thus it reduces the disease incidence by 66.3 to 78.1% as compared with control. In the same way, there was significant response of application of T. harzianum Th3 was observed on plant growth promoting parameters. at field level to increase number of pods per plant and shelling % and thereby produces maximum yield of 3.37 and 3.6 t/ha in Banswara and Jhabua district, respectively.