Some products of the degradation of hydrochlorofluorocarbons (HCFCs) by reaction with Cl atoms and O2 were studied by FT-IR. The degradation of CH3CCl2F(HCFC 141 b) was initiated by H abstraction, and then CH2CCl2F was oxidized, leading to formation of either HCHO and COClF or CCl2FCHO, and finally COClF, CO and CO2 were formed. In the addition reaction of Cl to CH2CCIF and subsequent reactions, both CH2ClCOF and COClF were observed. It was presumed that CHCl2CF3(HCFC 123) reacted with Cl and the produced radical was oxidized to CF3COCl. On the other hand, in the reaction of CHCl2CCl3 with Cl and O2, CCl3COCl, COCl2, CO and CO2 were produced and it indicates that C-C bond cleavage took place. CF3CF2CHCl2 (HCFC 225 ca) and CClF2CF2CHCIF(HCFC 225 cb) were degraded to CF3CF2COCl and CClF2CF2COF, respectively.