Rate coefficients ( k 4 ) for the reaction of hydroxyl radicals (OH) with methyl nitrate (CH 3 ONO 2 ) were measured over the temperature range 232-343 K using pulsed laser photolysis to generate OH and pulsed laser-induced fluorescence to detect it in real-time and under pseudo-first-order conditions. In order to optimize the accuracy of the rate coefficients obtained, the concentration of CH 3 ONO 2 (the reactant in excess) was measured on-line by absorption spectroscopy at 213.86 nm for which the absorption cross-section was also measured ( σ 213.86 = 1.65 ± 0.09 × 10 −18 cm 2 molecule −1 ). The temperature-dependent rate coefficient is described by k 4 ( T ) = 7.5 × 10 −13 exp(−1034 ± 40)/ T cm 3 molecule −1 s −1 with a room temperature rate coefficient of k 4 (296 ± 2 K) = (2.32 ± 0.12) × 10 −14 cm 3 molecule −1 s −1 where the uncertainty includes the statistical error of 2 σ and an estimation of the potential systematic bias of 5%. This new dataset helps to consolidate the database for this rate coefficient and to reduce uncertainty in the atmospheric lifetime of CH 3 ONO 2 . As part of this study, an approximate rate coefficient for the reaction of H-atoms with CH 3 ONO 2 ( k 9 ) was also derived at room temperature: k 9 (298 K) = (1.68 ± 0.45) × 10 −13 cm 3 molecule −1 s −1 . Temperature dependent rate coefficients ( k 4 ) for the reaction of OH with CH 3 ONO 2 .