Measurements of the X-ray photoelectron spectroscopy (Xp.s.) valence-band spectra of crystalline and amorphous poly(tetrahydrofuran) are reported. The experimental data are analysed on the basis of theoretically simulated Xp.s. valence-band spectra of model molecules. Differences in the spectra of poly(tetrahydrofuran) in amorphous and crystalline phases are interpreted in terms of differences in the conformational characteristics of the macromolecular chains.