A simple and selective procedure for the determination of vinorelbine, a new semi-synthetic vinca alkaloid, is presented. The method is based on ion-exchange high-performance liquid chromatography on normal-phase silica with fluorescence detection, combined with liquid-liquid extraction using diethyl ether for sample clean-up. The absence of endogenous interferences and the excellent chromatographic behaviour of vinca alkaloids provides accurate results even at low concentrations. The limit of determination in plasma is 1.5 micrograms/l (500-microliters sample). Reproducible recoveries in urine were obtained if 10-50 microliters of sample were processed supplemented with 500 microliters of blank plasma.