The kinetic features of the degradation of cumene hydroperoxide (ROOH) catalyzed by phenol sulfides (PS), which had been previously studied experimentally, was investigated using computer simulation. The ROOH decomposition in the presence of PS is a complex, multistage, autocatalytic process in which an effective degradation catalyst forms from a reactant phenol sulfide. A concentration effect, which manifested itself as a decrease in the complete ROOH conversion time with an increase in the initial concentration and of a more complete use of PS at high ROOH concentrations, was observed in this process.