Following the solar proton event (SPE) of July 13, 1982, an increase in the strength of nitric oxide &Ggr; bands was observed in spectral scans of the atmospheric albedo made by the solar backscattered ultraviolet instrument on Nimbus 7. Analysis of the (10), (01), and (02) &Ggr; band strengths allows us to estimate the cumulative amount of nitric oxide above an altitude of 50 km. We observe an increase in nitric oxide in southern hemisphere high latitudes following the SPE amounting to about 5¿1014 molecules per cm2 above an altitude of approximately 50 km. The observed increase persists until the middle of September. A similar increase is not observed in the northern hemisphere, indicating that under summer conditions the mesospheric/thermospheric NO distribution returns to normal within a few days after the end of an SPE.