The research was carried out to evaluate the in-vitro antimicrobial activity and phytochemical constituents of Cassia occ dential s. Cassia leaves were collected from Kacha town in Niger State and extracted using methano , hexane, chloroform and water extraction methods. Serial concentrations: 50 60, 70, 80, 90 and 100 % methanol, hexane, chloroform and aqueous extracts were prepared and sterilized. The bacterial isolates used; E. coli, P. multocida, S. typhi, S. typhimurium, S. pyogenes, S. pneumoniae and K. pneumoniae were authenticated using biochemical and serological methods. The suspens on (0.5) of each bacterial isolate was prepared in isotonic sodium chloride. The disc agar diffusion method was performed on 70 Mueller-Hinton agar p ates, 10 per microorganism , using serial diffusion concentrat on: 500, 600, 700, 800, 900 and 1000 mg o hexane, methanol, chloroform and water. The results showed that all the extracts of Cassia occidentalis have antimicrobial activity on E col at concentrations between 900-1000 mg. E. coli was most susceptible to hexane extract at concentration ranges between 500-1000 mg, there was no antimicrobial activity exhibited against the other tested microorganisms Phytochemical analyses showed the presence of alkaloid, tannin, saponin, glycoside and flavonoid, steroid was absent.