The Measurement of Air Pollution from Satellite (MAPS) experiment measured the distribution of middle tropospheric carbon monoxide (CO) from the space shuttle during October 1984. The data represent average mixing ratios in the middle troposphere between 57¿N and 57¿S. Approximately 75,000 individual CO measurements were obtained during the 9-day mission. The data are presented in maps that show the CO mixing ratios averaged over 5¿ latitude by 5¿ longitude areas for 6 days of the mission. Comparisons with concurrent, direct measurements taken aboard aircraft show that the inferred concentrations are systematically low by 20--40% depending upon which direct measurement calibration standard is used. The data show that there are very large CO sources resulting from biomass burning over South America and southern Africa. Measured mixing ratios were high over northeast Asia and were highly variable over Europe. ¿ American Geophysical Union 1990