Absorption by sulfur hexafluoride (SF6) has been detected in high-resolution infrared solar spectra of the lower stratosphere and upper troposphere. The identification is based on measurements of the intense, unresolved &ngr;3 band Q branch at 947.9 cm-1 in solar occultation spectra recorded near 31 ¿N and 47 ¿S latitude by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer on April 30 to May 1, 1985, during the Spacelab 3 shuttle mission. Vertical SF6 volume mixing ratio profiles have been retrieved using an onion-peeling nonlinear least squares spectral fitting procedure with SF6 line-by-line spectroscopic parameters generated recently by Bobin and coworkers from their analysis of the SF6 &ngr;3 band. Between 12 and 18 km altitude, the region over which the altitude with an average measured value of 1.42 parts per trillion by volume (pptv) at 31¿N latitude. There is evidence for a decline in the SF6 volume mixing ratio with increasing altitude between 18 and 22 km, but the results are not conclusive because of the weakness of the absorption. Absorption by the SF6 Q branch is below the noise level of the spectra at tangent heights above ~22 km. The measurements are compared with previously reported values and discussed in terms of the atmospheric lifetime of SF6, the long-term trend of atmospheric SF6, and the possible role of SF6 as an atmospheric greenhouse gas. ¿ American Geophysical Union 1990