For the identification and quantitative analysis of methamphetamine and its metabolites in the urine from a habitual user of the stimulant, the combined method of gas chromatography and mass fragmentgraphy was developed. The proportion of methamphetamine and its metabolites to the excreted matter is as follows : amphetamine 7.5%, p-hydroxymethamphetamine 6.45%, p-hydroxyamphetamine 0.35%, and norephedrine 0.23% respectively.