Cocaine use has increased dramatically in the United States during the past decade. The life-threatening cardiovascular and central nervous system complications of cocaine have been well documented; however, few studies have examined the risks of cocaine use during pregnancy. In this report the perinatal outcome data of 70 women receiving care at the Perinatal Center for Chemical Dependence of Northwestern University, whose pregnancies were complicated by cocaine abuse, were compared with those of matched control subjects. The use of cocaine during pregnancy was associated with lower gestational age at delivery, an increase in preterm labor and delivery, lower birth weights, and delivery of small for gestational age infants.