A simple , rapid and sensitive spectrophotometric method for the determination of microgram amounts of chlorpromazine Hydrochloride drug in aqueous solution is described. The method is based on the oxidative coupling reaction between chlorpromazine hydrochloride and N,Ndimethyl-p-phenylenediaminedihydrochloride (DMPD) in the presence of sodium periodate and hydrochloric acid to form an intense red colored product with maximum absorption at 525 nm. Beer's law is obeyed over the concentration range of(4-34) µg.ml-1 with moler absorptivity of 9.239x10 3 l. mol-1. Cm-1 and sandell's sensitivity of 0.038 µg.cm-2. The method does not resort to temperature control or to solvent extraction. The optimum conditions for all color development are described and the proposed method has been successfully applied for the determination of chlorpromazine Hydrochloride in bulk drug and pharmaceutical preparations (Largactil drug).