The kinetics and mechanism of the reaction of chlorine atoms with acrylonitrile (CH2CHCN) (1) have been studied by the mass spectrometric discharge-flow method in the temperature range (260-333) K and at a total pressure between 0.5 and 3 Tort. At 1.0 Torr the following Arrhenius expression for the rate constant has been obtained from the kinetics of Cl radical consumption in excess of CH2CHCN: k(1) = (5.2 +/- 1.6) x 10(-14) exp[(1400 +/- 100/T)] cm(3) molecule(-1) s(-1). The reaction is found to proceed through an addition mechanism involving a relatively stable adduct. The atmospheric significance of the present results for acrylonitrile is also discussed. (C) 2003 Elsevier B.V. All rights reserved.