The rate of the thermooxidation of lactam-based polyamides, independent of oxygen pressure was measured. The intensity of chemiluminescence, changes in molecular weight and the content of end-groups in the polymer were followed. The oxidation rate, chemical changes of polymers and intensity of chemiluminescence in the course of oxidation were found to be dependent on the content of foreign groups in the polymer, on the structure and concentration of end-groups, and on the structures incorporated into the molecules by side reactions during polymerization. The relation between the intensity of chemiluminescence and the rate of oxidation consumption differed profoundly for various polyamides.