The kinetics of degradation of intrazole [1-(pchlorobenzoyl)-3-(1 H-tetrazol-5-ylmethyl)indole] in solution was investigated at 65 ± 0.1° at constant ionic strength of 0.5 over a wide pH range. The observed rates, followed by measuring intact intrazole, obeyed first-order kinetics. The catalytic effect of a phosphate buffer was found to be greater than the acetic acid catalysis. The apparent rate of hydrolysis of intrazole increased with the increasing concentration of hydrochloric acid. Primary salt effects were observed in both acidic and basic solutions. The rate of hydrolysis decreased in acidic and alkaline solutions, with increasing concentrations of ethanol in the solvent system. The apparent heats of activation for intrazole degradation in solutionwere determined to be 19.87 kcal./mole in 0.1 N HCl, 21.40 kcal./ mole in pH 4.10 acetate buffer, 20.30 kcal./mole in pH 8.0 phosphate buffer, and 7.25 kcal./mole in pH 9.10 and 10.10 borate buffers. From the rate-pH profile, the pH of minimum degradation or maximum stability of the compound under buffer-free conditions was found to be 3.20. The products of hydrolysis formed in acid and alkali-catalyzed degradation of intrazole were identified by TLC. A mechanism consistent with the above observations is proposed.