Bacterial vaginosis is a clinical condition caused by replacement of the normal hydrogen peroxide producing Lactobacillus sp. in the vagina with high concentrations of characteristic sets of aerobic and anaerobic bacteria. Bacterial vaginosis is the most prevalent cause of vaginal discharge or malodor, although 50 percent of women who meet the criteria for this condition are asymptomatic. Bacterial vaginosis is reported in 10 to 41 percent of women, and new evidence has shown association with maternal and fetal morbidity. Studies have shown that spontaneous abortion, preterm labor, premature birth, preterm premature rupture of the membranes, amniotic fluid infection, postpartum endometritis, and postcesarean wound infections are increased because of infection with bacterial vaginosis during pregnancy. Clinical trials demonstrated important reductions in many of these adverse events with appropriate screening and antimicrobial treatment protocols. New low-cost, diagnostic, point-of-care screening tools are available for rapid screening of patients, affording the physician the opportunity to potentially make a dramatic clinical and cost impact in preventing preterm birth and the costly sequelae of prematurity. Practicing physicians need to be aware of current guidelines for screening and treating pregnant patients for bacterial vaginosis. The authors recommend that all pregnant women be screened and treated with the Centers for Disease Control and Prevention (CDC-P) recommended oral regimens early in pregnancy. Each treated women should be evaluated for "test of cure" 1 month after treatment. Mothers likely to benefit from "screen and treat" approaches include 1) those with the highest concentrations of genital anaerobes and mycoplasmas, 2) women with prior preterm birth or who have low body mass (BMI < 19.8 kg/m2), 3) those with evidence of endometritis before pregnancy, and 4) those who are treated with oral agents effective for both presumed intrauterine mycoplasmas and other bacterial vaginosis flora (i.e., oral clindamycin or erythromycin and metronidazole).