The laboratory infrared spectrum of 13C monosubstituted ethane has been obtained at high resolution (0.0025 cm-1) using the McMath Fourier transform spectrometer at Kitt Peak National Observatory in May 1990. A preliminary analysis of the &ngr;12 rQ0 branch (substituted species) suggests that its intensity is 1.15¿0.05 times stronger than the equivalent &ngr;9 branch in the normal 12C2H6 species. This result leads to a correction of a previously published estimate for the 12C/13C ratio in the atmosphere of Jupiter from ~94 to ~106. ¿ American Geophysical Union 1991