Quantitative infrared measurements of ethane (C2H6) in the upper troposphere and lower stratosphere are reported. The results have been obtained from the analysis of absorption features of the v 9 band at 12.2 Urn, which have been identified in high-resolution balloon-borne and aircraft solar absorption spectra. The balloon-borne spectral data were recorded at sunset with the 0.02 cm -1 resolution University of Denver interferometer system from a float altitude of 33.5 km near Alamogordo, New Mexico, on 23 March 1981. The aircraft spectra were recorded at sunset in July 1978 with a 0.06 cm -1 resolution interferometer aboard a jet aircraft at 12 km altitude, near 35°N, 96°W. The balloon analysis indicates the C2H 6 mixing ratio decreased from 3.5 ppbv near 8.8 km to 0.91 ppbv near 12.1 km. The results are consistent with the column value obtained from the aircraft data.The atmospheric chemistry of C2H 6 involves losses controlled by OH and C1 and the production of CO and PAN In the troposphere, the loss of C2H6 is controlled mostly by OH. In the lower stratosphere, C2H, reacts rapidly with C1 and its vertical profile is controlled by the distribution of CI and OH (Rudolph et al., 1981;Aikin et al., 1982;Singh and Salas, 1982). The sources of C2H 6 are not yet well known. Measurements of C2H~ obtained with a cryogenic collection technique indicate a steep decrease in mixing ratio with altitude and have been interpreted as indicating a lower Cl-atom concentration in the lower stratosphere than predicted by models (Rudolph et al., 1981;Aikin et al., 1982). Additional measurements of the C2H0 profile are useful as an indirect means of studying OH and C1 in the upper troposphere and lower stratosphere.In this paper, we confirm the identification and report the quantitative analysis of absorption features in the v9 band of C2H 6 in high resolution absorption spectra of the