This study endeavored to determine the incidence of intrauterine cocaine exposure in a socioeconomically mixed suburban setting. It also assessed the effectiveness of an anonymous questionnaire in eliciting information on maternal use of illicit drugs during pregnancy. Meconium was collected from 500 consecutively born infants and analyzed for the presence of cocaine and its metabolites. An anonymous two-page questionnaire also was distributed to all postpartum mothers. Of the infants' mothers, (73.2%) were covered by some form of insurance (private), whereas 26.8% either had no insurance or were covered by Medicaid (clinic). Fifty-nine (11.8%) babies tested positive for cocaine. The meconium of 6.3% of the babies whose mothers had private insurance tested positive, while the meconium of 26.9% of the babies whose mothers had Medicaid or no insurance tested positive. 316 (63.2%) of the mothers returned a questionnaire. 73% had private insurance and 27% were covered by Medicaid (clinic). Only five mothers with no insurance or covered by Medicaid admitted using cocaine. It appears that neonatal exposure to cocaine may be an even greater problem than previously imagined, particularly in the private population. In addition, anonymous maternal self-reporting forms probably will not be helpful in identifying infants at risk for illicit exposure to drugs.