Methyl bromide (CH3Br) is a hazardous ozone depleting substance that is released to the atmosphere from natural and anthropogenic sources. Within the troposphere CH3Br is removed through reaction with (OH)-O-center dot and Cl-center dot radicals. Here, quantum and statistical mechanical calculations are combined with existing experimental data in order to arrive at improved rate coefficient expressions for the reaction of methyl bromide with (OH)-O-center dot and Cl-center dot from 200 to 2000 K. For CH3Br + (OH)-O-center dot k = 9.8 x 10(14) (T/298) 2.9 exp(-3000/RT) and for CH3Br + Cl-center dot k = 1.5 x 10 (12) (T/298)(2.0) exp(-2900/RT), with k in cm(3) molecule(-1) s(-1), T in K, and R = 1.987 cal mol(-1) K-1. (C) 2018 Elsevier B. V. All rights reserved.