ZnSe homogeneity region was studied by direct physico-chemical method in 730-1320 K temperature range. It was established that the homogeneity region included stoichiometric composition and solidus lines both from Zn- and Se-rich sides demonstrated the retrograde behavior. Comparison of ZnSe nonstoichiometry with ionized defect concentrations at S-ZnSe-L-(Zn)-V equilibrium had let us assert that at the examined conditions the dominant point defects are electrically neutral. Nonstoichiometry analysis of ZnSe crystals grown from melt under high pressure and from vapor by the Markov-Davydov technique showed that there were Se-excess over stoichiometry in melt grown ZnSe and Zn-excess close to stoichiometry in vapor grown crystals. (C) 2014 Elsevier B.V. All rights reserved.