Rate coefficients for the reaction CH2CHCHO + Cl --> P (1) at different temperatures (260-333 K) have been determined using a discharge flow-mass spectrometric technique (DF-MS) at low total pressure. k(1) was found to be pressure-independent at T = 298 K in the pressure range 0.5-3 Torr. The temperature dependence of the reaction rate constant has been determined under pseudo-first-order kinetic conditions in excess of acrolein over Cl atoms, with no significant changes in the rate constant. At room temperature and 1 Torr, products of both abstraction (1a) and addition (1b) channels have been detected. The branching ratio for abstraction channel at 298 K and 1 Torr was determined as 0.83 +/- 0.13 and led to HCl and CH2CHCO* radical. The temperature dependence of this abstraction channel has also been studied, giving the Arrhenius expression k(1a) = (5.4 +/- 2.0) x 10(-10) exp{(-748 +/- 110)/T} cm(3) molecule(-1) s(-1) in the temperature range 260-333 K. The results obtained are related to previous studies, and the mechanism of reaction is discussed.