The conformational equilibrium of trans-2,3-dihydroxytetraline was studied by the1H-NMR method, on the basis of the methin protons signal width measurements. The metylene and methin protons of the alicyclic tetralene-diol ring represent the AB CC' A'B' system /Fig. 1,2/. The spectrum data are time averages of the values corresponding to the diaxial /a,a/ and diequatorial /e,e/ conformations and depend upon their ratio. The methin protons /C C'/ signal width /J, the distance measured between outer strong peaks, or at the 1/4 signal height/ equals JAC+ JBC+ JA'C+ JB'C1.Itis also represented by the equation J = nJaa + /1-n/Jee, where Jaa and Jee are the signal widths in the diaxial and diequatorial forms respectively, and n is the molar fraction of the diaxial form.