A complex of N,N'-ethylenebis(salicylideneiminato)diaquochromium(III) chloride, [Cr(salen) (H2O)(2)]Cl as a model of glucose tolerance factor (GTF) was characterized and its decomposition mechanism was studied by TG. The IR spectrum of the product of thermal decomposition was examined for the first stage. Kinetic results were obtained from the analysis of TG and DTG curves with four different methods.