The laboratory infrared spectrum of ¹³C mono‐substituted 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 ν₁₂ ^rQ₀ branch (substituted species) suggests that its intensity is 1.15±0.05 times stronger than the equivalent ν₉ 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.