Mixtures of starting ZnO and Cr2O3 powders in equimolar quantities were mechanically activated by grinding using a high energy vibro-mill for 0, 40 and 80 minutes. Qualitative X-ray diffraction analysis made after sintering at 900degreesC for 240 min showed the presence of a well-crystallized spinel-type phase, ZnCr2O4, in all examined samples. A detailed structural analysis of lattice parameters, average primary crystallite sizes, and crystal lattice microstrains was made by the pattern decomposition technique, performed in accordance with the procedure based on the KOALARIET-XFIT program. Due to importance of cation distributions for the chemical and physical properties of spinels, a study of site occupation factors of ZnCr2O4 spinels, i.e. changes in the stoichiometry, was conducted. Calculations based on atomistic methods for the simulation and description of perfect and defect spinel ZnCr2O4 crystal lattices were made, and the presence of individual structural defects was determined.