Ferrite samples of the composition Cu1 − xZnxFe2O4 (0.0 ≤ x ≤ 1.0) were synthesized by chemical coprecipitation. The samples exhibited a single-phase cubic spinel structure and the saturation magnetization of the samples was found to increase with increasing Zn content, when x ≤ 0.4; and then decreased with increasing x. The dependence of magnetization on cation distributions in the ferrite samples has been estimated using a quantum-mechanical method proposed by our group. Estimated cation distributions obtained by fitting the magnetic moments of the samples were used to perform Rietveld fitting for X-ray diffraction patterns. The acceptable error parameters in the Rietveld fitting indicate that the estimated cation distributions in the samples are reasonable.