The present paper focus on the phytochemical screening and antimicrobial activity of Phyllanthus narayanaswamii (Euphorbiaceae), a critically endangered and endemic species to the East Godavari & Visakhapatnam hills of North Eastern Ghats. In the present study the alcoholic extracts of leaves, shoot and root of P. narayanaswamii were studied for their antibacterial activity by agar disc diffusion method against both Gram positive, Gram negative and one fungal strain. It was observed that, alcoholic extracts of leaf showed the highest antimicrobial activity against the pathogenic microorganisms followed by shoot and root extracts. The minimum inhibition and minimum bacterial concentrations (MIC and MBC) were determined by microdilution method using 96-well microtiter plate method. As the disc dosage level increases the inhibitory effect also increased.