The rate constants for the gas-phase reaction of OH radicals with nitromethane, deutero-nitromethane and propane have been determined at 295 ± 2 K and a total pressure of approximately 1 atm; a photolytic relative technique and an absolute method were applied. Methyl nitrite was used as the OH source in the relative method. In the absolute technique, pulse radiolysis was combined with kinetic spectroscopy. H₂O-Ar mixtures were irradiated and the OH kinetics recorded by following the transient light absorption around 309 nm. The results are compared with literature data.