Proton spectroscopy has been employed to determine the conformational free energy (− ΔG0) of a formyl group bonded to a cyclohexane ring. Thecis- andtrans-4-t-butylderivatives were used as models for the axial and equatorial formyl groups in cyclohexanecarboxaldehyde and 1-methylcyclohexanecarboxaldehyde. The wiggle-beat technique was used to determine the spectral line positions and separations because of the relatively small differences involved. The − ΔG0values were found to be relatively insensitive to solvent polarity and concentration over the range 10–50 mole %. For 10 mole % solutions the average value of − ΔG0CHOwas found to be 1.38 kcal/mole.