An easy and simple spectrophotometric method was described for estimating chlorpromazine Hydrochloride drug in aqueous solution. Where The method was adopted on oxidative coupling reaction of the drug with p- nitro aniline in the presence of ceric(IV) ammonium nitrate and hydrochloric acid solution an orange-brown product dye was obtainded with maximum absorption at 525 nm. with moler absorptivity of 9.24×103 l. mol-1. cm-1 and sandell's sensitivity of 0.0385 µg.cm-2 Beer's law is obeyed over the concentration range of (12-46) µg.ml-1. The method was applied successfully for the estimating the drug it's on pure condition or in pharmaceutical preparations (Largactil drug).).