The molecular structure of cyclobutane has been analysed from its previously measured dipolar couplings. Assuming that the cyclobutane molecule oscillates between two equivalent bent conformers, the C-H bond length decreases from an anomalous value of 1·144 Å to 1·097 Å when harmonic vibration corrections are applied to observed dipolar couplings. The optimized values for the remaining geometric parameters are: 0·26 Å for the puckering amplitude, 109.8° for the HCH bond angle and 3.5° for the methylene rocking coordinate. The inversion barrier (ΔV) value cannot be determined because the RMS deviation between observed and calculated direct couplings remains practically unaltered for ΔVvalues greater than 4 kJ mol-1.