A decrease in the diurnal temperature range has been identified throughout this century in many of the world's land-based climate records. However, documentation of the seasonality, magnitude, and geography of these changes has been hampered by the lack of homogeneous maximum and minimum temperature measurements over most of the planet. In this investigation, we attempt to use satellite-based measurements of tropospheric temperatures to assess spatial and temporal trends in the diurnal temperature range over the period 1979 to 1994. Although quite exploratory and preliminary in nature, we find that the satellite-based estimates of the diurnal temperature range are (1) larger over land areas than ocean areas, (2) high in summer, particularly in low latitudes, and low in winter, especially in the higher latitudes, and (3) decreasing substantially in the winter season for the land areas between 30 ¿N and 60 ¿N. The results are potentially compromised by many factors including orbital drift problems and changes in satellites. Despite the potential pitfalls of the satellite-based measurements in this investigation our findings support other results showing a reduction in diurnal temperature range in the midlatitudes of the northern hemisphere during the low-sun season. ¿ American Geophysical Union 1996