ABSTRACT This study was carried out with an objective to investigate the antibacterial and antifungal potential of seeds of Cassia fistula Linn. The aim of the study is to assess the antimicrobial activity and to determine the zone of inhibition of extracts on some bacterial and fungal strains. In the present study, the microbial activity of chloroform extracts of seeds of Cassia fistula Linn. (An ethno medicinal plant) were evaluated for potential antimicrobial activity against medically important bacterial and fungal strains. The antimicrobial activity was determined in the extracts using agar disc diffusion method.. Crude extracts of Cassia fistula exhibited moderate to strong activity against most of the bacteria tested. Zones of inhibition of extracts were compared with that of different standards like Ampicilline, Ciprofloxacin, Norfloxacin and Chloramphenicol for antibacterial activity The extracts showed antibacterial activities comparable with that of standard against the organisms tested. The results showed that the remarkable inhibition of the bacterial growth against the tested organisms. The phytochemical analyses of the plants were carried out. The microbial activity of the Cassia fistula was due to the presence of various secondary metabolites. Hence these plants can be used to discover bioactive natural products that may serve as leads in the development of new pharmaceutical research activities. Keywords: In vitro Antibacterial activity, antifungal activity, Cassia fistula, bacterial pathogens, secondary metabolites