The radiation-induced reaction between benzene and chlorine in the liquid phase has been studied using a continuous stirred-tank reaction system. The reaction was studied at higher exposure dose rates [2.66 × 1017 eV/(ml min)] and lower chlorine concentrations [0.025 M] than heretofore reported. In agreement with previous studies of both the ultraviolet- and the gamma-ray-induced reactions, the reaction was found to be a chain reaction, first order with respect to chlorine concentration, resulting in the formation of a mixture of the stereoisomers of 1,2,3,4,5,6-hexachlorocyclohexane. No effects of temperature or reaction-vessel surface-to-volume ratio were observed. An observed decrease in reaction rate with increasing holdup time in the reaction vessel was attributed to buildup of an inhibitor during the course of the reaction.