Nitrogen NMR shieldings (Δσ=-δ on the frequency scale of chemical shifts), measured by high-precision 14N NMR and bulk susceptibility corrected, of 20 nitroalkanes in dilute solutions in cyclohexane and in acetone are reported, including vic-dinitro, gem-dinitro and trinitro structures and tetranitromethane. The data obtained for cyclohexane solutions yield an excellent linear correlation with theoretical shieldings calculated for the corresponding isolated molecules by the semi-empirical TNDO/2 method. The NO2 nitrogen shieldings of nitroalkanes are shown to depend linearly on the net charges of the corresponding nitro groups, each taken as a whole, but there is no correlation with the atomic charges of the nitrogen atoms concerned. Thus, the nitrogen shieldings seem to provide a measure of electron-acceptor or electron-donor strength of the substituted alkyl system bound directly to the nitro group. Solvent polarity effects on the shieldings are discussed. The nitro group nitrogen shieldings are shown to be generally sensitive to conformational effects, particularly in sterically hindered molecules, and to provide insight into conformational or rotamer equilibria in nitroalkane systems. Ab initio calculations of the shieldings of some simple nitroalkanes, using the Hartree–Fock/GIAO approach, are reported. They indicate that the semi-empirical method employed, combined with the experimental data, yields results which are comparable to those obtained by the ab initio method, as far as relative shieldings are concerned. ©1998 John Wiley & Sons, Ltd.