A large number of mesospheric temperature inversion layers have been observed locally in recent decades, notably by the network of French lidars. It is shown in this paper that the Improved Stratospheric and Mesospheric Sounder on board the Upper Atmosphere Research Satellite is able to detect the presence of temperature inversions, and thus allows the study of their occurrence and characteristics on a global scale. During December 1991, inversions of large amplitude (greater than 20 K) are seen almost every day, especially in mid latitudes, with extent varying typically from 105 to 106 km2. Several particularly large inversions were observed at the end of the month. Their correlation with assimilated stratospheric winds is consistent with the interpretation that gravity waves propagate unfiltered through the stratosphere in the regions of strong winds, and break in the mesosphere. The combination of high resolution lidar measurements and global satellite coverage is expected to lead to a better understanding of this significant feature of the winter mesosphere at middle latitudes. ¿ American Geophysical Union 1995