The Cl-atom initiated oxidation of CH3Cl has been studied at 296 K using two different FTIR/environmental chamber systems. In the presence of NO, the carbon-bearing products observed are HCOCl, HCHO, and CO, with yields in 700 Torr of air of (56 +/-10), (32 +/- 6), and (12 +/- 5)%, respectively. This product distribution is different from previous studies conducted in the absence of NO, in which a nearly 100% yield of HCOCl was obtained. The different product distribution observed in the presence of NO is attributed to the formation and subsequent decomposition of chemically activated CH2ClO radicals, formed in the exothermic reaction of CH2ClO2 with NO.