Observations of backscattered radiation from an orbiting geophysical observatory (Ogo) satellite for the period September 1967 to February 1968 have been used to determine the global distribution of ozone at different levels in the middle and upper stratosphere (30--55 km). The derived distribution show significant seasonal and geographic variations with important differences indicated between winter and summer hemisphere distributions. The Ogo-derived distributions are compared with other observations (rocket and satellite) and with photochemical calculations. It is suggested that the ozone mixing ratio in the high-latitude winter hemisphere can be accounted for by transport processes up to about 40--45 km and by temperature-sensitive chemistry above.