Preterm birth rates are higher for African Americans than for whites, but the risk for recurrence is not well defined. We tested the hypothesis that the base and recurrence rates for premature births are higher for African Americans than for whites. We recruited a cohort of African-American and white women giving birth to singleton infants between 1988 and 1993 at Perinatal Network, a Midwest urban teaching hospital. These women had known reproductive history, delivered two or more singletons, and had no planned abortions, miscarriages, or induced preterm labor. Premature infants were born at less than 37 completed weeks of gestation. The total preterm birth rate among African Americans was 24.5%, significantly higher than the 11.1% for whites (relative risk, 2.22; confidence interval, 1.79 to 2.75). The preterm birth rate among African Americans for the second pregnancy was 30.6%, significantly higher than the rate of 18.2% for the first pregnancy and 24.5% for the third and fourth pregnancies. The preterm birth rates for whites were 11.7% for the first pregnancy, 9.8% for the second, and 12.9% for the third and fourth pregnancies, which were not significantly different from each other. Considering only the first two pregnancies, recurrence accounted for 32.6% of all premature births for both African Americans and whites. After the second pregnancy, 68% of African-American and 41.7% of white premature babies were born to women who had previous preterm infants. We conclude that preterm births are relatively common for African Americans and whites in the first two pregnancies. Women, particularly African-American women with a previous preterm birth at either the first or second pregnancy, require more specific management to prevent recurrence of preterm birth.