The aim of our study was to determine the prevalence of cocaine abuse, by means of positive urine toxicology screens or targeted questionnaire, among women in labor at our hospital. The prospective study included 1773 women who delivered consecutively in our institution. All of them underwent a standardized questionnaire including drug use and demographic data. Urine samples were obtained during labor. Urine toxicology screens for cocaine and its metabolites, opiates, and ethanol were performed by enzyme multiplied immunoassay technique. Information was coded in order to maintain anonymity. Among the 1773 women in labor we screened, the mean age was 27.8 years and the overall prevalence of a positive questionnaire for cocaine was 0.3% and a positive urine toxicology was 0.8%. Results by drug and by demographic items are analysed. There was a substantial denial of cocaine use among the toxicologically positive patients, since only 43% of them referred its use at any time during pregnancy, in conclusion, the use of illicit drugs is common among pregnant women in our institution, but cocaine does not seem to be as prevalent as it is in the USA, while in the labor room most women with a positive test do not refer the use of the drug. Urine toxicology screening increases the rate of detection of substance abuse in this population of women. These studies are necessary to target educational programs among pregnant women.