The elementary reaction of formaldehyde (H2CO) with chlorine atom has been experimentally investigated by the time-resolved infrared emission spectroscopy. The nascent products HCO and HCl (v less than or equal to 3) are observed. The major product channel has been identified as Cl + H2CO --> HCl + HCO. Theoretical calculations have revealed that the mechanism is a nearly barrierless peripheral hydrogen abstraction reaction. (C) 2003 Elsevier Science B.V. All rights reserved.