We report measurements of the J=1→0 and J=2→1 emission lines of mesospheric CO at 115 and 230 GHz, respectively, and the first use of these emission lines to obtain CO volume mixing ratio profiles. The radiative transfer equation that connects the observed transition line shape and the volume mixing ratio profile is presented, and the process for inverting the line shape to obtain a profile is discussed. The profiles resulting from our measurements are similar to but not identical with other experimental and theoretical results, and they show lower CO at altitudes below 50 km than expected from in situ measurements.