Solid-phase extraction techniques were evaluated for the treatment of urine samples in the analysis of amphetamine and methamphetamine by normal-phase high-performance liquid chromatography with 1,2-naphthoquinone 4-sulphonate. Six different packing materials were tested, and the results obtained are compared with those obtained in a classical liquid-liquid extraction with n-hexane. Different clean-up eluents and the influence of pH of urine have been tested. The intra-day and inter-day precision, the accuracy of the method and the addition of beta-phenylethylamine as internal standard were also studied.