This work aims to evaluate the antimicrobial potential of halophytic plant, Sesuvium portulacastrum (L.) against, some plant and human pathogens. Plant parts of S. portulacastrum were collected from the mangrove habitats of Coringa Reserve Forest near Kakinada, Andhra Pradesh, India. Plant parts are dried and extracts were obtained successfully with hexane, chloroform, methanol and water, using Soxhlet extraction apparatus. Agar well diffusion method has been used to determine the antimicrobial activity of plant extracts against some gram positive bacteria (Bacillus subtilis, Bacillus megaterium and Lactobacillus acidophilus), gram negative bacteria (Escherichia coli, Enterobacter aerogenes, Enterobacter cloace and Klebsiella pneumonia) and fungal species (Candida albicans, Mucar recemosus, Rhizoctonia solani, Rhizopus stolonifer and Saccharomyces cerevisiae). The hexane, chloroform extracts showed minimum antimicrobial activity when compared to methanolic and water extracts. Water extract of S. portulacastrum showed appreciable antimicrobial activity against all bacterial and fungal strains. It reveals that this halophytic species has antimicrobial compounds which can act against microorganisms and they can be used in the treatment of infectious diseases caused by pathogenic microorganisms.