The kinetics of the gas-phase reactions of chlorine atoms with bromomethane CH3Br and D-bromomethane CD3Br was studied experimentally. The relative rate method was applied using Cl + CH4 as the reference reaction. The rate constants for H-abstraction from CH3Br (k(H)) and D-abstraction from CD3Br (k(D)) were measured in the temperature range of 298-527 K and at a total pressure of 100 Torr. The temperature dependencies of the rate constants are described by the expressions: k(H) = (1.43 +/- 0.22) x 10 (11) x exp(-1040 +/- 30/T) and k(D) = (1.36 +/- 0.31)x10 (11) x exp(-1595 +/- 30/T) cm(3) molecule (1) s (1). The kinetic isotope effect, described by the ratio k(H)/k(D), was found to be (1.07 +/- 0.14) x exp(555 +/- 20/T). (C) 2010 Elsevier B. V. All rights reserved.