Abstract: A new spectrophotometric method has been developed for the determination of chlodiazepoxide. It is based on a reaction of charge transfer with dinitrophenol in borax buffer solution. The apparent molar absorptivity is 1.48×10³ L/(mol·cm). The calibration curves are linear in the concentration range of 3～96 μg/mL. The composition of complex of chlodiazepoxide with dinitrophenol is 1:1. This proposed method was found to be simple, quick and accurate for the determination of chlodiazepoxide in tablets.