The method is based on the oxidation of chlorpromazine with ammonium metavanadate in pH 2. 4 solution, the absorbance of coloured compound was measured at 530nm. Calibration graphs are linear over the concentration range 0 similar to 250 mu g/mL. The apparent molar absorptivity was 1. 28 X 10(3) L . mol(-1) . cm(-1). The proposed method was applied to the determination of chlorpromazine tablets with satisfactory results.