Abstract: Background and Objectives: Wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici (Sacc.) W., is one of the most economically important disease of tomato occurring world-wide. In the present study, the mycoparasitism inhibitory affects of three Trichoderma species (T. viride, T. harzianum and T. koningi) on the growth of the causal agent of tomato Fusarium wilt (Fusarium oxysporum f.sp. lycopersici) were investigated by dual culture under in vitro conditions. Materials and Methods: Already identified Trichoderma species viz. Trichoderma harzianum, Trichoderma viride and Trichoderma koningii were taken for the present experiment used to check their relative viability against Fusarium oxysporum f. sp. lycoperisci by dual culture techniques. All the isolates of Trichoderma were evaluated for the growth pattern on five different media along with different temperature and pH range. Results: Trichoderma harzianum inhibited maximum radial growth (75.7%) of Fusarium oxysporum f. sp. lycopersici pathogen during the experiment followed T. viride. During the same study all these Trichoderma isolates were evaluated on five different solid media for assessing growth and sporulation and the maximum radial growth of Trichoderma harzianum were found in Potato Dextrose agar whereas the lowest growth was observed in Trichoderma selective medium. Similarly, excellent growth of Trichoderma spp. was found at temperature range of 25±2°C, while 5.0-7.0 pH was found the most favourable for the growth and sporulation of Trichoderma spp. Conclusion: Out of all the three species of Trichoderma, the maximum inhibition of the test pathogen was furnished by Trichoderma harzianum. On the basis of present study the fungal bioagents, might be exploited for future plant disease management programs (DMP) to save environmental risk.