AbstractThe proton chemical shifts of dyad, triad, and tetrad protons in an isolated chain of polypropylene were calculated, taking into account its configurations and conformations using Pople's approximation.The calculations were carried out as functions of four parameters, i.e., a, Δψ, ω, and fr: a represents the ratio of the magnetic anisotropy of the CHCH3 bond to that of the CHCH2 bond, Δψ the deviation for the rotational angle, ω the statistical weight corresponding to the four‐bond interaction, and fr the amount of the racemic units contained in a chain. By introducing the parameter, a, the observed orders of dyad and triad protons were well explained and the value of a was in the range of about 1,10 to 1,25. However, the agreement between the observed and calculated results was insufficient with respect to the large difference between syn and anti protons and the order of tetrad protons. Here, a priori probabilities of specified conformations necessary to the estimation of the chemical shift were calculated using Flory's matrix method. These results were compared with the conformation of polypropylene obtained by Flory et al. and Zambelli et al.