Cassia fistula L. was examined for its in vitro antifungal potential against Ascochyta rabiei (Pass.) Lab., the causal agent of chickpea blight (Cicer arietinum L.). Screening bioassay with methanolic leaf and bark extracts were performed in vitro against A. rabiei. All the concentrations of methanolic leaf and bark extracts significantly reduced fungal growth. Leaf extract exhibited greater antifungal activity than the bark extract. Leaf extract was selected for bioassays guided fractionation. Methanolic leaf extract was partitioned among n-hexane, chloroform, ethyl acetate and n-butanol. Minimum inhibitory concentration (MIC) of the four separated fractions and a commercial synthetic fungicide (metalaxyl + mancozeb 72 WP) was investigated against A. rabiei. Chloroform fraction was found highly effective against A. rabiei with MIC value of 0.97 mg mL^-1 followed by ethyl acetate and n-hexane fractions.