A method using gas chromatography coupled to mass spectrometry for the determination of the cocaine (COC) pyrolysis product, anhydroecgonine methyl ester (AEME), in urine and hair is described. The same procedure allows the simultaneous determination of COC, benzoylecgonine (BZE), ecgonine methyl ester, and cocaethylene. The assay involves acid hydrolysis for hair, deuterated internal standards, a three-step liquid-liquid extraction, and derivatization with N,O-bis(trimethylsilyl) trifluoroacetamide plus 1% trimethylchlorosilane. Detector responses for analytes were linear over the concentration ranges of 0.2-50 ng/mg and 10-2000 ng/mL for hair and urine, respectively. Artifact formation of AEME during the injection was less than 1%. AEME was tested in 65 and 81 cases for hair and urine, respectively, where COC or BZE or both tested positive. Concentrations of AEME ranged from 0.2 to 2.4 ng/mg (n = 7) and from 4 to 226 ng/mL (n = 12) in hair and urine, respectively. Its presence was observed in few cases, clearly indicating that COC smoking is not frequent in France.