The aqueous, ethanolic, methanolic,petroleum ether and chloroform extracts of coccinia grandis, citrullus lanatus, momordica charantia, cucurbita pepo, (cucurbitaceae) leaves were evaluated for antimicrobial activity against bacterial strains such as E.coli, Bacillus subtilis. The invitro antimicrobial activity was performed by disc diffusion and well diffusion technique. Extracts were found to contain alkaloids, flavonoids, glycosides and carbohydrates by various phytochemical tests. Of the four extracts tested, aqueous ethanol extract was found to exert consistently better antibacterial activity than methanol extract. In conclusion, most of the cucurbitaceae plants contain nearly the same compounds and also exhibited antimicrobial activity against bacterial strains such as E.coli, B.subtilis.