The reaction of F atoms with CH₃Br at 296 K was studied using a pulse radiolysis/transient UV absorption spectroscopy absolute technique and a FTIR relative rate technique. The rate constant for this reaction was determined to be (4.46 ± 0.22) × 10^-11. The reaction proceeds via two channels, 69 ± 5%, via hydrogen abstraction giving CH₂Br radicals and HF, and 31 ± 5%, to give the adduct CH₃Br-F. In the FTIR system the observed rate constant was 69 ± 8% of that measured using the pulse radiolysis system because the CH₃Br-F adduct falls apart to re-form the reactants. The CH₃Br-F adduct reacts with NO, with a rate constant of (2.25 ± 0.14) × 10^-11 cm³ molecule^-1 s^-1, giving FNO as a product. There was no discernible reaction of the CH₃Br-F adduct with O₂ and an upper limit of 6 × 10^-15 cm³ molecule^-1 s^-1 was derived for this reaction. The CH₃Br-F adduct absorbs strongly at 260-340 nm. The absorption cross section at 280 nm of the CH₃Br-F adduct was (2.06 ± 0.31) × 10^-17 cm² molecule^-1. A lower limit for the equilibrium constant was [CH₃Br-F]/([CH₃Br][F]) > 5 × 10^-16 cm³ molecule^-1 at 296 K. A lower limit of 12 kcal mol^-1 is estimated for the binding energy of the F atom in the CH₃Br-F adduct. The UV absorption spectrum of the CH₂BrO₂ radical was determined; at 250 nm σ = (3.4 ± 0.9) × 10^-18 cm² molecule^-1.