Summary. Gas chromatographic and mass spectrometric data concerning the analysis for certain sympathomimetie amines in blood samples from drivers are presented. In all cases where gas chromatography gave peaks at the correct retention times for amphetamine or phenmetrazine respectively, mass spectrometry confirmed the presence of the corresponding drugs in the extracts from blood. Drug-free blood samples gave neither gas chromatographic nor mass spectrometric responses at the retention times characteristic for amphetamine or phenmetrazine.Computer-drawn mass spectra of phenmetrazine are shown in Fig. 2. Analytical data obtained from twelve drivers and one hospital patient are collected in the table.