NO2 was measured in the stratosphere at night by means of a balloon-borne spectrometer, pointing at a bright rising star, in the 427 to 452 nm range. The vertical distribution of NO2 was deduced using the tangent ray technique between 23 and 38 km. The concentration was (6¿1.5)¿109 mol.cm-3 at 25 km, passing through a minimum of (2¿1)¿109 mol.cm-3 at 29 km and rising again up to (4¿0.8)¿109 mol.cm-3 at 32 km.