The kinetics of thermal degradation of standard and commercial polyethylene (PE) samples is investigated, by employing different methods like Flynn-Wall-Ozawa, Coats-Redfern, Kissinger, and Augis-Bennett. The order of reaction obtained was 0.741 and 1.124 for standard and commercial samples, respectively. The activation energy obtained in this way was 279.6-311.0 kJ/mol and 300.5-374.1 kJ/mol for standard and commercial samples, respectively, depending upon the method used. The activation energy obtained by different methods decreases in the order Flynn-Wall-Ozawa" Augis and Bennett" Kissinger" Coats and Redfern. It is observed that most of the methods deviated from the experimental results, in low (0.1-0.3) degree of conversion region but worked well in the middle (0.5-0.7) degree of conversion region. It has also been noticed that both the order and activation energy were slightly dependent over the heating rate and degree of conversion. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3511-3518, 2011