A new one-step process for synthesis and growth of zinc-germanium-phosphide, ZnGeP2 (ZGP), is reported for the first time herein using a three-zone resistance furnace by the horizontal gradient freeze technique. A safe and proper temperature scheme has been obtained for both synthesis and growth of ZGP crystals via the melt growth route from Zn, Ge and P powder. The prepared material has been investigated using powder X-ray diffraction which shows the correct ZGP tetragonal phase. EPMA results are also obtained to estimate the compositional homogeneity of the grown crystal.