Literary and experimental data on the ozonation kinetics of aqueous solutions and wastewater were analyzed. COD was suggested to be used as a kinetic parameter from the solution side. On the basis of the results obtained from the ozonation of model solutions and wastewater, the rate coefficient by COD of the reaction was shown to be constant during separate stages of the process. Due to the consumption of fast-reacting components and entering into the reaction of more slowly reacting intermediate products, the rate coefficient changed spasmodically with transition from one stage to another. The reaction order with respect to the COD of the solution was shown to be equal to the reaction order with respect to the pure component.