OBJECTIVE To determine whether analysis of amniotic fluid (AF) using solid-phase extraction and high-performance liquid chromatography is useful in detecting fetal exposure to cocaine and its metabolites. METHODS Amniotic fluid and urine samples were obtained from 23 subjects with documented cocaine abuse during pregnancy and five subjects without a history of cocaine abuse. Urine samples were also collected from all newborns. Urine samples were screened using conventional immunoassay techniques and confirmed with thin-layer chromatography. Using a modified solid-phase extraction procedure, we removed cocaine and its metabolites from all AF samples and from the newborn urine samples in which the initial screening was positive. Subsequently, we analyzed the extracts with high-performance liquid chromatography. RESULTS Cocaine or benzoylecgonine was detected in 74% of AF samples taken from the 23 known cocaine abusers. In these subjects, conventional maternal and neonatal urine toxicology screens were positive in 61 and 35%, respectively. Concentrations in AF ranged from 400 to greater than 5000 ng/mL for benzoylecgonine and from trace to 250 ng/mL for cocaine. Mean benzoylecgonine recovery from AF was significantly greater than from newborn urine (1800 versus 280 ng/mL, respectively; P < .0001). CONCLUSIONS Analysis of AF appears to be useful in detecting gestational cocaine exposure.