We report the results of a study of the daytime ion chemistry of NO+ using Atmosphere Explorer-C measurements made at altitudes above 155 km. We determine that the rate coefficient for dissociative recombination of NO+ as a function of electron temperature Te during the daytime is accurately represented by the expression 4.5¿10-7 (Te/300)-0.83, derived from laboratory measurements of Walls and Dunn. The total rate of recombination in the lower thermosphere is consistent with the rate of ionization produced by the AE-C reference spectrum of Hinteregger.