Reactions of fuel derived radicals, R, and oxygen, are of interest for low temperature combustion and autoignition. A method for measuring R + O-2 rate coefficients based on the real time regeneration of OH radicals following initiation of the reaction via OH + RH is presented; values for k(R+O2) can be extracted from the resulting biexponential OH profiles. The rate coefficient for the reaction of CH3OCH2, with O-2, at 29-483 K, in 4.1-32.6 Torr of nitrogen are reported. At room temperature, k(CH3OCH2+O2) = (0.94 +/- 0.04) x 10(-11) cm(3) molecule(-1) s(-1), where the error represents statistical uncertainty at the 2 sigma level.