Purpose: Interactions between bacterial vaginosis (BV) and inflammatory sexually transmitted infections, such as gonorrhea and chlamydial infection, are not well understood. Furthermore, evidence regarding the sexual transmission of BV is equivocal. Methods: We assessed associations between incident BV and incidences of gonorrhea and/or chlamydial infection (" gonorrhea/chlamydia" ), as well as similarities in associations for the two processes, among 645 female patients at a sexually transmitted disease clinic in Alabama followed prospectively for 6 months from 1995 to 1998. We identified predictors of both incident BV and gonorrhea/chlamydia and used bivariate logistic regression to determine whether these predictors differed. Results: Participants completed 3188 monthly, follow-up visits. Several factors associated with incident BV involved sexual intercourse: young age (<16 years) at first intercourse (adjusted odds ratio [aOR], 1.5; 95% confidence interval [CI], 1.1-1.9), recent drug use during sex (aOR, 1.7; 95% CI, 1.2-2.5), prevalent trichomoniasis (aOR, 2.8; 95% CI, 1.7-4.6) and incident syphilis (aOR, 9.7; 95% CI, 1.9-48.4). Few statistical differences between potential factors for BV and gonorrhea/chlamydia emerged. BV appeared to precede the acquisition of gonorrhea/chlamydia (pairwise odds ratio, 1.6; 95% CI, 1.1-2.3), and vice versa (pairwise odds ratio, 2.4; 95% CI, 1.7-3.5). Conclusions: Findings are consistent with a causal role of sexual behavior in the acquisition of BV and confirm that BV facilitates acquisition of gonorrhea/chlamydia and vice versa independently from other risk factors. © 2012.