A rapid and simple procedure based on gas chromatography-mass spectrometry (GC-MS) is described for determination of Delta-tetrahydrocannabinol (THC), 11-hydroxy-Delta-tetrahydrocannabinol (THC-OH) and 11-nor-Delta-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in meconium using Delta-tetrahydrocannabinol (Delta-THC) and deuterated THC-COOH as internal standards. The biological matrix was subjected to liquid-liquid extraction after enzyme hydrolysis for conjugated analytes.Chromatography was performed on a fused silica capillary column and analytes were determined in the selected-ion-monitoring (SIM) mode. The method was validated in the range 20 to 500 microg/g using 1g of meconium per assay. The method was applied to the analysis of meconium in a cohort of newborns to assess eventual fetal exposure to cannabis. Within positive samples, THC-COOH and THC-OH (range: 33.7 to 182.1 and 20.7 to 493.3 microg/g, respectively) were both present in the majority of cases with only 1 specimen with THC-OH as the most abundant metabolite and 2 with THC only.