Abstract : A spectrophotometric analysis for valuing microgram quantities of Chlorpromazine hydrochloride drug in aqueous solution is defined that is simple, fast, and sensitive. The process is based on the formation of an intense red colored substance with maximum absorption at 530 nm from a transition metal complex between Chlorpromazine hydrochloride and Lead (IV) oxide (metal) in the existence of hydrochloride acid. With a Molar absorptivity of 2.9394 x104 l.mol-1.cm-1 and a Sandells sensitivity 0.014μg.Cm-2, Beer's Law is followed over a concentration range of ( 1- 20) μg.ml-2. The planned process has been effectively useful for assessment of Chlorpromazine hydrochloride in pharmaceutical preparations (Largactil drug)and bulk drug, and The optimum conditions for all colour production are defined. In this methodology, shared excipients and additives had no effect.