Polarization measurements of the primary X-ray beam produced by thick copper and tungsten anodes are reported and formulas derived for integrated intensities of Bragg reflections in energy-dispersive diffractometry with the polarization of the primary beam taken into account. It was found that for an angle of 45° between the scattering plane and the plane containing the electron beam and the primary beam, the influence of polarization vanishes, while it increases as the angle changes from 45° to either 0 or 90°. For the latter values, the influence of polarization is considerable at high photon energies and at scattering angles close to 90