The cation distribution in a natural magnesium aluminium chromite spinel (cubic, space group Fd-3m), Al(0.41)Cr(1.42)Fe(0.65)Mg(0.4)O(4), was determined by electron-microprobe analysis, Mossbauer spectroscopy and single-crystal X-ray analysis. Several structural models of the octahedral and tetrahedral cation distributions were tested; the most probable is (Mg(0.40(11))(2+),Al(0.28(5))(3+),Fe(0.39(4))(2+))[Al(0.13(5))(3+),Cr(1.42(6))(3+),Fe(0.26(4))(3+),Phi(0.19)]O(4)(2-), where (...) and [...] represent the tetrahedral and octahedral sites, respectively, and Phi represents a vacancy.