In this study in order to determine prevalence of Gardnerella vaginalis and sensitivity of the organism to antimicrobial agents specimens were treated in the outpatient clinic of Taleghani hospital in Tehran. Specimens were considered positive for bacterial vaginosis (BV) which were positive three times out of four. The tests include; finding clue cell, amine test, homogenesity of this discharges, and PH. To isolate the bacteria, discharges were cultured on human blood bilayer twin 80 ( HBT), the isolated strains were tested for antibiotic sensitivity. The results indicated that 67.5℅ of the patients had bacterial vaginosis. Based on the results of culturing the isolated colonies, and the results of the biochemical conformational tests, 23.8℅ of the patients were infected with Gardnerella vaginalis, out of these 82℅ were in people who had bacterial vaginosis. No significant correlation was found between the presence of Gardnerella vaginalis and number labour's and abortions, however there was a significant correlation with the application of IUD among the subjects. Study of the stained smears made from the discharges, indicated that there was a significant correlation between reduction of lactobacilli population, elevation in the number of gram variable bacteria, and the presence of Gardnerella vaginalis ( p<0.05). The results obtained from antibiotic sensitivity tests indicated that the isolated strains of Gardnerella vaginalis was sensitive to ampicillin (10 mg), sulfomethoxazol + trimethoprim (25 mg) , nitrofurantoin (300 mg) , metronidazole (50 mg), nitrofurantoin 300 mg, chloramphenicol (30 mg) , tetracycline (30 mg), and resistant to metronidazole (10 mg).