We have studied the kinetics of the thermal decomposition of cellulose nitrate at 167.4°C in a vacuum for the range of nitrogen contents from 0.09 to 13.45%. The rate constants of the initial and autocatalytic stages have been determined. The method of nitrating cellulose with a mixture of the vapors of water and nitric acid in a previously evacuated sealed vessel has no special effect on the thermal kinetic properties of the cellulose nitrate produced. It is shown from the experimental results that at 167.4°C the rate constant for the loss of NO₂ groups in the primary position is about 14 times less than for those in the secondary position.