The mean particle size, the microstrains, and the degree of inhomogeneity in compacted and dispersed nanostructured materials are determined from the broadening of diffraction reflections. A method is described for separating the contributions from the small size of particles, the microstrains, and the inhomogeneity of materials to the broadening. The application of the proposed method is illustrated using a nanocrystalline powder of tungsten carbide WC.