Condition for epitaxial growth of silver chloride on silver iodide has been studied. Hexagonal plate crystals of β-AgI were prepared by gel method and AgCl crystals grew on it by evaporation of a variety of AgCl-amine solutions. AgC1 crystals covered with [111] faces were grown from aqueous ammonia solution, those with [110] faces were from aqueous pyridine solution and those with [100] faces were from aqueous ethylamine solution. AgCl crystals having [111] faces grew epitaxially on fitting their triangular lattice to that of [0001] face of AgI crystal. On the contrary, those having [100] and [110] faces did not grow epitaxially. At nucleation stage, two dimensional planar nuclei were formed at first. As lattice constants are different between AgCl and AgI, the effect of solvent to determine the face index becomes stronger than that of base lattice, and nuclei have [100] or [110] planar lattices. They contact AgI not with [111] faces but with [100] or [110] faces randomly and they do not grow epitaxially.