A multiwavelength spectrometer with limb-scanning optics was developed to make NO2 measurements in the stratosphere. The instrument observes light scattered by aerosol particles and air molecules and measures the differential attenuation of light at different wavelengths by NO2. A vertical profile of NO2 was determined from the brightness measurements, using the results of a single scattering model. The instrument was flown from Palestine, Texas, and observed the stratosphere from an altitude of 33 km at 32¿N, 98¿W for a period of several hours on the afternoon of June 17, 1983. The mixing ratio of NO2 was observed to be (3.5¿0.8) parts per billion by volume (ppbv) at 28 km, in reasonable agreement with solar occultation measurements. The time rate of change of the NO2 concentration at 28 km is estimated at (0.18¿0.06) ppbv per hour at 2200 coordinated universal time (CUT). ¿ American Geophysical Union 1988