The results of theoretical and experimental investigation of O-17 NMR chemical shifts for a number of epoxidic compounds are reported. The calculations were performed for the MP2/6-311G(d) level reference geometries using the GIAO and CSGT methods within the coupled Hartree-Fock perturbation theory. Various basis sets were applied in calculations of the chemical shifts. The performance of recently developed magnetically consistent basis sets and their advantages over the standard ones are discussed. The obtained results allow one to assign NMR signals for epoxides for which experimental data were obtained for the mixtures of stereoisomers.