Stratospheric NO2 was measured at night by means of a balloon-borne spectrometer pointing at a bright rising or setting in the 440-nm region. Four flights were made from May 1976 to September 1981. For the last flight, two vertical profiles of the NO2 mixing ratio were recorded within a time span of 2 hours. The two profiles were identifical within the error range and the average profile is in good agreement with the results of previous flights. The NO2 mixing ratio increased from about 6.1 ppb at 26 km to about 13.2 ppb at 35 km. It favorably compared with theoretical predictions about 30 km and with observations of NOX=NO+NO2 by solar occultation.