Objective To determine predictors of bacterial vaginosis (BV) and the level of three common BV-related microorganisms by racial group. Methods Prospective cohort study of 1,886 pregnant women. BV was measured with Nugent’s Gram Stain criteria, smoking status with urinalysis of cotinine levels, and stress with Cohen’s perceived stress scale. Results 73% of the cohort were African-American and 37% were BV positive. Smoking, numerous sexual partners, and single status were related to both BV positivity as well as higher levels of Gardnerella ssp. among African-American pregnant women. Age and history of STD were associated with BV positivity, and history of STD and insurance status were associated with Gardnerella ssp. levels in non-African-American pregnant women. Contrary to prior research, perceived stress and douching were not associated with BV positivity or the level of any of the BV-related microorganisms in this cohort. Conclusions A greater number of modifiable, behavioral-related risk factors predicted BV and the level of BV-related microorganisms among African-American compared to non-African-American pregnant women. A deeper understanding of predictors of BV and related microorganism levels by racial group may help eliminate critical disparities with respect to BV positivity and adverse pregnancy outcomes, including spontaneous preterm birth.