Concentrated samples of stratospheric air were obtained with flow-through, liquid-nitrogen-cooled samplers at pressure altitudes of 18.3 km and 21.3 km aboard U-2 aircraft, and at 28.3 km and 35.9 km aboard a balloon platform. Dichlorodifluoromethane (CF2Cl2) and nitrous oxide (N2O) were separated by gas chromatography and their concentrations were determined with an electron capture director. The mixing ratios of CF2Cl2 and N2O are reported for locations in California, Oregon, Texas, and Quebec, Canada. The observed mixing ratios compare within a factor of 2 to those reported by other investigators and show a more rapid decrease with altitude than predicted by a two-dimensional (2-D) model.