The possibilities of comparing kinetic curves obtained under isothermal and nonisothermal conditions are considered with the aim of elucidating the influence of experimental conditions on the mechanism of the process. It is shown that the affinitive transformations used in isothermal and nonisothermal kinetics are not identical, and lead to curves which cannot be compared one with another. A special method of comparing kinetic curves is proposed. This method relies on analyzing the shape of the affinitively transformed isothermal kinetic curve and the nonisothermal one previously reduced to the isothermal form. The results of testing the proposed method on model data prove its efficiency. © 1991.