In this work, Gaussian-3 (G3) and complete basis set (CBS) composite energy methods combined with canonical transition state theory (CTST) and Rice-Ramsperger-Kassel-Marcus (RRKM) theory were applied to the kinetic modeling of the 1-chloroethyl radical decomposition reaction: *CHCICH3 -> CHCICH2 + *H. Experimental thermodynamic and kinetic data were employed to evaluate the accuracy of these two composite energy methods. For this reaction, both composite energy methods proved to have good agreement with the experimental data, which indicates they are reliable methods for studying reactions involving other chlorinated hydrocarbons (CHCs). A kinetic model of this reaction with pressure and temperature effects was proposed. For P < P-0, k (s(-1)) = (7.32 x 10(10))P-0.69 e((-18 727.10/T)); for P >= P-0, k (s(-1)) = (3.74 x 10(13)) e((-20 648.10/T)), where P is pressure in units of kPa, T is temperature in units of Kelvin, and P-0 = (8.42 x 10(3)) e((-2 782.61/T)). Without performing additional costly calculations, these equations can be easily implemented in different industrial applications with various reaction conditions.