Objective:To evaluate the antibacterial effect of aqueous and ethanolic moringa leaf extracts (Moringa oleifera) on the growth of gram-positive and negative bacteria. Methods:Paper disks were soaked with 100, 200, 300 and 400μL of extract at 20 g/180 mL and 10 g/190 mL. All extracts were tested against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923), Vibrio parahaemolyticus, Enterococcus faecalis (ATCC29212), Pseudomonas aeruginosa (ATCC27853), Salmonella enteritidis (IH) and Aeromonas caviae. The susceptibility tests were performed using the modified disk diffusion method. Results:The strains E. coli, P. aeruginosa and S. enteritidis (IH) were resistant to all treatments. In general, disks with 400μL extract were the most efficient against S. aureus, V. parahaemolyticus, E. faecalis and A. caviae. Conclusions: The study indicates a promising potential for aqueous and ethanolic Moringa leaf extracts as altative treatment of infections caused by the tested strains.