Recent reports of adverse pregnancy outcomes associated with prenatal cocaine exposure have raised questions about the actual numbers of infants who are exposed to cocaine in utero. Whereas toxicologic urine screens obtained at delivery can detect cocaine use in the preceding few days, they fail to yield a comprehensive picture of use during and immediately before pregnancy. According to postpartum self-report, 15% of a teaching hospital sample and 3% of a private hospital sample of mothers had used cocaine during pregnancy or in the previous month (total = 876). Rates at the teaching hospital reflect a fifteenfold increase over the past 12-year period, when compared with previously obtained data. Cocaine users were significantly more likely to report that they drank alcohol, smoked cigarettes, and took other illicit drugs during pregnancy than women who denied using cocaine. Mothers at highest risk for cocaine use were those who were black (20%), were single-separated-divorced (24% to 33%), and had less than a high school education (21%).