The flash photolysis‐resonance fluorescence technique has been utilized to measure the rate constants for the reactions of chlorine nitrate (ClONO2) with two stratospheric radicals, O(³P) and OH. Both rate constants were measured at a pressure of 20 Torr and a temperature of 245 K. The reactions with their corresponding rate constant in units of cm−3molecule−1s−1are: O(³P) + ClONO2→ Products, k1= (2.0 ± 0.2) × 10−13; OH + ClONO2→ Products, k2= (3.7 ± 0.2) × 10−13.The above results, coupled with the photolysis rate of ClONO2, indicate that these chemical degradation pathways contribute less than 10% to the removal of ClON