Syzygium caryophyllatum L. is a small tree or large shrub grow widely mainly in the tropical area. It is native to India and China. S. caryophyllatum L. belonging to the family Myrtaceae is taken for screening antimicrobial activity. Ethanolic extract of the leaves of Syzygium caryophyllatum was screened for antibacterial activity using Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Activity of ethanolic extract was good when compared to Ampicillin. The antimicrobial activity was determined by Agar diffusion method and also MIC technique. From the result it was found that ethanolic extract of the leaves of Syzygium caryophyllatum exhibited good antibacterial activity against these gram +ve and gram –ve microorganisms.