Abstract: The rate constants k₅ for the reaction of OH with N₂O have been determined in a fast-flow discharge system using the reaction of hydrogen atoms with NO₂ as the source of OH. The decay of OH in excess N₂O at a total pressure of 4.0+0.1 lorr in Ar as the carrier gas was followed by resonance fluorescence at 309.0 nm at temperatures from 273 to 363K in2.6-cm-diameter flow tube coated with boric acid.k₅=（1.59+1.06）×10^-14cm³molecule^-1s^-1at 293K and the rate constant was observed to be independent of temperature over the range studied.