The aim of this study was to evaluate the antimicrobial activities of two green seaweeds: Enteromorpha intestinalis and Ulva lactuca collected from the Matla river of Indian Sunderbans Delta. Both seaweeds showed antibacterial activities against several gram positive, and gram negative human pathogens obtained either clinically or from microbial type collection centre. Several pathogens among the clinically isolated strains were multidrug resistant isolates. Among the different solvents tried, best activity was noted in the n-Hexane fraction. Along with the antimicrobial activities, both seaweeds also showed antifungal activities. The MIC values of the activities were determined by disc diffusion assay and macrodilution assay. The phytochemical screening revealed the presence of xanthoprotein, flavonoid, tannin, alkaloid, glycosides, saponins and cardiac glycosides.