Independent measurements of nitrogen oxides (NOx=NO+NO2) were made in proximity to lightning using both a chemiluminescent NOx analyzer and an absorption spectrometer (COSPEC) tuned to the NO2 absorption at Langmuir Laboratory (elevation 3300 m), near Socorro, New Mexico. COSPEC data obtained from three separate lightning events, two from distant storms and one from direct observation of the plume from a single flash a few hundred meters away, yielded 4 to 10¿1026 molecules NO2/flash after normalizing to flashes at sea level. Measurements from the NOx analyzer during two different thunderstorms indicated that the ratio of NO to NOx can remain high (0.7-0.8¿0.1) for several minutes after a flash. Combining the data from the COSPEC with the NOx analyzer yields a production rate of approximately 3¿1027 molecules NOx/flash. If 100 flashes/second is an assumed global lightning flash frequency, this production rate becomes 100 TgN/yr (TgN/yr=1012 g nitrogen/yr) as an order of magnitude estimate. ¿ American Geophysical Union 1989