A high-performance liquid chromatographic method has been developed for the determination within tumour cells of a new vinca alkaloid, vinorelbine. Extractions of vinorelbine from cells were carried out using absolute ethanol. The extracts were injected into a reversed-phase system consisting of two Novapak C18 columns connected in series. The mobile phase was acetonitrile-phosphate buffer, pH 2.7 (60:40, v/v). Using a fluorescence detection, the limit of determination was 8 pmol injected. This method would be suitable for studying the cellular pharmacokinetics of vinorelbine in patients.