We identified maternal demographic, behavioral, and medical history factors that predict bacteriuria (that is, symptomatic and asymptomatic urinary tract infection) at prenatal care initiation. We applied logistic regression modeling to data from all prenatal care recipients who delivered during 1990–1993 and resided in selected North Carolina counties (N = 8037), omitting those with diabetes mellitus, human immunodeficiency virus, or structural urologic abnormalities. The two strongest predictors of bacteriuria at prenatal care initiation were an antepartum urinary tract infection prior to prenatal care initiation (for whites, adjusted prevalence odds ratio (POR) = 2.5, 95% CI 0.6–9.8; for blacks, POR = 8.8, 95% CI 3.8–20.3) and a pre-pregnancy history of urinary tract infection (POR = 2.1, 95% CI 1.4–3.2). For white women only, education beyond high school and age ≥30 years were inversely associated (POR ≤ 0.6). Sickle cell hemoglobin nearly doubled the prevalence odds for bacteriuria among African-Americans (POR = 1.9, 95% CI 1.0–3.5), whereas African-Americans with normal hemoglobin had reduced prevalence odds compared with whites (POR = 0.6, 95% CI 0.4–0.9). This study suggests predictors not considered before, including race controlling for sickle cell disease or trait and antepartum urinary tract infections prior to prenatal care. (Epidemiology 1999;10:282–287)