Using a chemiluminescent detector, vertical profiles of NO were measured during the STRATOZ III mission from June 4--26, 1984. The mission's flight track started close to Paris, went west across the North Atlantic, south along the east coast of North America and the west coast of South America. It returned north along the east coast of South America, crossed the Atlantic around the equator and continued north along the west coast of North Africa and continental Europe. It covered the latitudes between 67¿N and 60¿S and the altitudes between 0 and 12 km. The coastal profiles in the northern hemisphere and in the tropics exhibited a C shape, with higher NO concentration values in the planetary boundary layer and the upper troposphere, whereas the measurements over the ocean showed low values in the upper troposphere. The NO mixing ratios in the southern hemisphere, south of 20¿S latitude, were lower than in the northern latitudes and showed little increase in the upper troposphere. The two-dimensional NO distribution along the flight track is derived, and the possible sources of the NO in the high troposphere are briefly discussed. ¿ American Geophysical Union 1988