The differences in the phenotype and genotype of Gardnerella vaginalis isolates from patients with bacterial vaginosis (BV) and from patients without BV are unknown. In our study, 43 isolates of G. vaginalis were examined for biotype (hippurate hydrolysis, lipase, and beta-galactosidase activity), sensitivity to metronidazole, and genotype. Of the 117 women visiting the gynecology clinic at Rush-Presbyterian-St. Luke's Medical Center who were included in the study, 27.4% were found to have BV. G. vaginalis was found in samples from 87.5% of women with BV, from 34.0% of women with intermediate BV, and from 26.4% of women with healthy vaginal ecosystems. Among patients with G. vaginalis, biotypes 7 and 8 were isolated from 32% and 20% of patients, respectively. Biotype 5 was predominantly associated with a healthy vaginal ecosystem (P=.0004). Biotypes 5 and 7 were the most resistant to metronidazole. No specific phenotype or genotype of G. vaginalis causes BV.