3-(7'-Methoxycoumarin-3'-carbonyl)-benzoxazoline-2-thione (MCBT) was synthesized as a precolumn fluorescent labeling reagent for amantadine for use in high-performance liquid chromatography (HPLC). Amantadine was derivatized quantitatively into a fluorescent compound through the amino group by treatment with MCBT at room temperature for 5 min in aqueous 95% acetonitrile solution in the presence of 4-dimethylaminopyridine. The derivative was subjected to HPLC on TSK gel ODS-80TM (250×4.6 mm i.d.) with methanol-water (10 : 1) as the mobile phase and monitored with an excitation wavelength of 355 nm and an emission wavelength of 405 nm. The limit of detection was 2.0 μg/ml in the urine. This method was satisfactory with respect to simplicity and precision to quantify amantadine spiked in the urine.