The integration of 1 H and 13 C NMR spectra, at -90 β’ C in CS 2 /CD 2 Cl 2 (9 : 1), for the trans-3-chlorocyclohexanol (1), trans-3bromocyclohexanol (2), and trans-3-methoxycyclohexanol (4) showed that the equatorial-axial (ea) conformer occurs as ca 63, 63, and 69% in the conformational equilibrium, respectively. This corresponds to the following G ea -ae values (from 1 H spectrum): -0.32 Β± 0.01, -0.32 Β± 0.04, -0.48 Β± 0.05 kcal mol -1 ; and to (from 13 C spectrum): -0.31 Β± 0.04, -0.35 Β± 0.05, and -0.44 Β± 0.01 kcal mol -1 , respectively, in very good agreement within both series. Thus, although bromine is bulkier than chlorine, the 1,3-diaxial steric effects are similar in these equilibria. However, the integration of 1 H NMR spectrum for the trans-3-methylcyclohexanol (3) gave 90% of the 3ae conformer in the equilibrium, at -90 β’ C on CS 2 /CD 2 Cl 2 (9 : 1), corresponding to a G ea -ae value of 1.31 Β± 0.02 kcal mol -1 . The values obtained through the additivity rule, with data from monosubstituted cyclohexanes ( G Ad = G X + G OH ), for compounds 1, 2, and 4 (-0.37 Β± 0.15, -0.34 Β± 0.09, and -0.46 Β± 0.04 kcal mol -1 , respectively) are in very good agreement with the experimental values, but it is significantly smaller for compound 3 (0.79Β±0.02 kcal mol -1 ). Theoretical calculations through different levels of theory (HF/6-311+g * * , B3LYP/6-311+g * * , MP2/6-31+g * * , and CBS-4M) showed that CBS-4M is the best method for the study of conformational equilibria for these systems, since it provides G ea -ae values similar to the experimental values.