The vertical distribution of stratospheric nitrogen dioxide was measured during the Atmospheric Environment Service STRATOPROBE projects in August of 1975 and 1976. Vertical profiles of NO2 are determined by measuring the NO2 absorption of sunlight from a balloon platform during sunrise and sunset and inverting the absorption curves. A total of four sunrise/sunset pairs of observations were obtained from balloon flights of August 10 and 17, 1975 and August 19 and 28, 1976. The measurements show significant stability of the NO2 profile from flight to flight with variations of less than 15% between individual profiles. The average NO2 concentration at sunset was found to increase from about 0.3 ppbv at 10 km to 10 ppbv at 35 km. At sunrise the concentrations increase from 0.2 ppbv at 10 km to 5 ppbv at 35 km.