A high-performance liquid chromatographic method for the quantitation of carvedilol in human plasma is presented. The method is based on protein precipitation with methanol, concentration of the supernatant by evaporation and reversed-phase chromatography with fluorimetric detection. The separation was performed on a Develosil 3 micro m ODS 100 x 4.6 mm I.D. column and the mobile phase consisted of acetonitrile-30 mM potassium dihydrogenphosphate buffer, pH 2 (30:70 v/v). With only 250 micro l of plasma used for sample preparation, the limit of quantitation 1.3 ng/ml was achieved. Dihydroergocristine mesylate was used as the internal standard. The between-day precision expressed by relative standard deviation was less than 6% and inaccuracy does not exceed 3%. The assay was used for pharmacokinetic studies.