When the hosts are susceptible and the environment is feasible the viable fungal pathogens cause many plant diseases. The diseased plant fails to produce a healthy yield and also declines its viability. To inhibit the effect of fungal pathogens either natural or synthetic fungicides are applied. The present investigation deals with In vitro antifungal activity of the synthetic fungicide Bavistin (50% WP) on Sclerotium rolfsii Sacc. using poisoned food technique. Mainly 0.2mg, 0.4mg, 0.6mg, and 0.8mg of fungicide were incorporated into four different 100ml PDA media and obtained specific concentrations such as 10ppm, 20ppm, 30ppm, and 40ppm respectively, and then poured into four different Petri plates. It was found very toxic at 40ppm and the growth was completely inhibited whereas the lower concentrations such as 30ppm, 20ppm, and 10ppm showed various degrees of inhibition on soil-borne fungus Sclerotium rolfsii Sacc.