The rate constant of the reaction of BrO with CH3O2 was determined to be k(1) = (6.2 +/- 2.5) x 10(-12) cm(3) molecule(-1) s(-1) at 298 K and 100-200 Torr of O-2 diluent. Quoted uncertainty was two standard deviations. No significant pressure dependence of the rate constants was observed at 100-200 Torr total pressure of N-2 or O-2 diluents. Temperature dependence of the rate constants was further investigated over the range 233-333 K, and an Arrhenius type expression was obtained for k(1) = 4.6 x 10(-13) exp[(798 +/- 76)/T] cm(3) molecule(-1) s(-1). The product branching ratios were evaluated and the atmospheric implications were discussed.