Green electroluminescence emission is observed on some ZnSe single crystals prepared by the sublimation method. Studies are made on the electroluminescence under microscope, on emission spectra, wave form of the emission and dependence of the electroluminescence on the current flow. A close correlation was found between the electroluminescence and rectification properties of the crystal. From experimental results, the electroluminescence is concluded to be caused by acceler-ated electrons exciting the emission centers while passing through small and localized npn junctions in regions which are considered to be of p type. When the applied voltage is high, a glow-like emission is observed, which suggests the breakdown of some of npn junctions.