The Ar-matrix IR spectra of 2-propanol and its OD, D 7 and D 8 isotopologues were measured and interpreted by means of DFT and MP2 calculations. The harmonic and anharmonic vibrational frequencies of two stable 2-propanol rotamers were predicted at the B3LYP/cc-pVTZ level. Theoretical IR spectra were elucidated by using the potential energy distribution; allowing for the detailed assignment of observed bands. Anharmonic calculations permitted us to assign several Fermi resonances. In contrast to earlier rotational and computational studies, the present IR spectra have given no evidence of equilibrium between the rotamers of 2-propanol.