INTRODUCTION:Recently, using plant drugs against drug resistant bacterial infections is gaining special importance. Umbilicus intermedius boiss (nafe venus) is a traditional remedy used for treatment of infectious disease in western of Iran. This study aims to the evaluate inhibitory effect of alcoholic and aqueous extract of Umbilicus intermedius boiss (nafe venus) on Staphylococcus aureus and Pseudomonas aeruginosa in vitro. METHODS: The plant was collected and dried in warm and low humidity environment. Alcoholic and aqueous extract prepared according to the standard method. Clinical samples of Staphylococcus aureus and Pseudomonas aeruginosa was used. The inhibitory effect of alcoholic and aqueous extract was done in the Muller Hinton Agar medium by disk diffusion method. RESULTS: Inhibitory zone of alcoholic extract on S. aureus and P. aeruginosa was 14mm and 10mm respectively. Zone of inhibition of aqueous extract for S. aureus and P. aeruginosa was 20mm and 14mm respectively. MIC of aqueous extract for S. aureus and P. aeruginosa was 10 and 15ugr/ml and MIC of alcoholic extract was 15 and 20ugr/ml respectively. MBC of aqueous extract for S. aureus and P. aeruginosa 15 and 25ugr/ml and MBC of alcoholic extract were 25 and 30ugr/ml respectively. CONCLUSION: The aqueous extract had a higher antibacterial effect than the alcoholic extract. This extract had a higher effect on gram negative bacteria than a gram positive.