In situ sampling of cloud droplets by aircraft in Oklahoma in 1997 is used to evaluate a ground-based remote sensing technique for retrieving profiles of cloud liquid-water content. The technique uses vertically pointing measurements from a high-sensitivity millimeter-wavelength radar and a collocated dual-frequency microwave radiometer to obtain height-resolved estimates of the liquid content of stratiform clouds. Comparisons with the aircraft measurements are made for 16 overpasses through thin cloud layers within a 1.5-km radius of the remote sensor site. Over a range of liquid-water contents from 0.04 to 0.57 g m-3 the mean difference between the aircraft and the radar/radiometer values was 0.02 g m-3, and the maximum difference was 0.09 g m-3. Although the number of comparisons is limited, these results suggest that the ground-based estimates may be sufficiently accurate for many scientific purposes. ¿ 2000 American Geophysical Union