A new method to determine the absolute configuration of organic compounds is described. It is a modern variation of Mosher's method and is designated 'modified Mosher's method'. The method uses MTPA moiety as a chiral auxiliary, the phenyl group of which affects the chemical shifts of the protons in the molecule. The compound possessing a secondary alcohol moiety is esterified with (R) and (S) -MTPA acids, and the respective diastereomers are subjected to NMR analyses to assign the signals of as many protons as possible. The pattern of arrangement of Δδ values defined as Δδ=δ_S-δ_R for each proton leads to the absolute configuration of the compound in question. Versatility and limitation of this new method are discussed.