Well　crystallized　ZnO　powders　with　various　morphologies　such　as　hour　glass-shaped,　shortened　prismatic,　flake-like　and　prismatic　form　have　been　synthesized　by　adopting　the　system　of　Zn(Ac)(2)-KOH-H2O　via　a　hydrothermal　process　at　200degreesC　for　2　h.　It　was　found　that　the　as-synthesized　hour　glass-shaped　ZnO　crystallites　are　asymmetric　both　in　shape　and　stoichiometry:　while　the　atomic　ratio　of　O/(Zn+O)　at　the　bigger　end　ranges　from　about　60%　to　40%　along　the　polar　axis　of　the　hour　glass-shaped　ZnO　crystallites,　the　atomic　ratio　of　O/(Zn+O)　at　the　smaller　end　remains　almost　constant　at　approximately　50%.