Biological control with microbial antagonists is considered an alternative approach for controllingrnplant diseases. Trichoderma species are one of the potential fungal biocontrol agents in suppressionrnof soil-borne and foliar pathogens. The present study aimed to evaluate, test and characterizernpotential biocontrol agents of Trichoderma isolates against two pathogenic isolates ofrnColletotrichum species under in vitro condition. Infected sorghum leaf, sheath, stalk and soilrnsamples were collected from different ecological habitat of Welkait district for the isolation ofrnColletotrichum isolates. The study examined the effect of pH and temperature on the myceliarngrowth and spore yield of Trichoderma isolates in broth culture. In this study, the in vitro potentialrnof 7 Trichoderma isolates were evaluated against two pathogenic Colletotrichum isolates in dualrnculture techniques and through production of volatile and non-volatile inhibitors. Pathogenicity testrnwas confirmed Colletotrichum isolates as one of the fungal organisms responsible for sorghumrnanthracnose disease. It was observed that the optimum pH and temperature for maximum mycelialrngrowth and spore yield produced by Trichoderma isolates in broth cultures was pH 7.5 and 25OC,rnrespectively. In vitro screening results showed that the proportion of isolates with antagonisticrnactivities was the highest for the AUC-1 isolate followed by AUC-2 isolate. In vitro confrontationrnanalysis revealed that all Trichoderma isolates were highly antagonistic against AUC-1 whereasrnAUT-97, AUT-131, AUT-11 and AUT-12 isolates displayed over 75% inhibition of mycelialrngrowth of AUC-2 isolate (P