[en] Absolute rate constants for the reaction of OH radicals with H₂ and NO (M = Ar, N₂) have been determined at 298 +- 1⁰K using a flash photolysis-resonance fluorescence technique. The rate constant for the reaction OH + H₂ was determined to be (6.97 +- 0.70) x 10^-15 cm³ molecule^-1 sec^-1 in good agreement with recent literature values. Rate constants for the reaction OH + NO + M (M = Ar) were obtained over the pressure region 26-655 torr, while a rate constant for M = N₂ was obtained at 25 torr total pressure. The low pressure third order rate constants for this reaction were determined to be (4.25 +- 0.43) x 10^-31 cm⁶ molecule^-2 sec^-1 (M = Ar) and (6.1 +- 0.7) x 10^-10 cm⁶ molecule^-2 sec^-1 (M = N₂), in good agreement with the available literature values. The bimolecular rate constants at 760 torr total pressure were determined to be (5.2 +- 0.8) x 10^-12 cm³ molecule^-1 sec^-1 for M = Ar and (6.1 +- 1.0) x 10^-12 cm³ molecule^-1 sec^-1 for M = N₂. A value of 8 x 10^-12 cm³ molecule^-1 sec^-1 was obtained as a probable lower limit for the limiting high pressure second order rate constant from an extrapolation of the data. (U.S.)