Today one of the greatest difficulties in oxidation reactions of drugs is the determination of in vivo oxidative stresses. In the present study, LMSP-UV1200 spectrophotometer is used to monitor the kinetics of oxidation of Propranolol hydrochloride (PPL) with 1-Chlorobenzotriazole (CBT) both in basic and in acidic medium. The PPL-CBT reaction progress has been monitored spectrophotometrically at λmax=314 nm (after using the excitation wavelength of PPL is 289 nm) over the temperature range 299-315 K. The redox reaction follows a rate law -d[CBT]/dt=K[PPL]a[CBT]b[H2O]. Where, a and b are one and two respectively. The oxidation of PPL with CBT is zero order with respect to acid and base. Variations of the ionic strength and the solvent dielectric constant have insignificant effect on the rate. An addition of the reduction product of CBT is BTA, to the reaction mixture also has no influence on the rate. A plausible reaction mechanism consistent with the observed kinetic data and thermodynamic parameters has been proposed in basic and acidic solutions.