The pulse radiolysis of SF₆/CH₃SCH₃/O₂/NO₂gas mixtures was used to generate CH₃SCH₂O₂radicals in the presence of NO₂. By monitoring the rate of NO₂decay using its absorption at 400 nm, rate constants for the reaction of CH₃SCH₂O₂radicals with NO₂were measured to be (9.2 ± 0.9) × 10^-12and (7.1 ± 0.9) × 10^-12cm³molecule^-1s^-1at room temperature in 1000 and 300 mbar of SF₆diluent, respectively. Results are discussed with respect to the atmospheric chemistry of dimethyl sulfide.