We have synthesized ZnO nanostructures by using simple horizontal chemical vapor deposition (CVD). Three different types of substrates, i.e., Si (111), oxidized Al/Si (111) and Al2O3 (0001); were used. In addition to the substrate types, the effects of substrate position in the alumina tube reactor were investigated. The morphologies and the structures were significantly changed depending on both the substrate type and position. Nanosheets, nanowires and rods were synthesized on the substrates placed on the alumina source while only nanowires were synthesized on the substrates placed on the side bar next to the alumina source boat. The structural and the optical properties of the nanostructures synthesized on oxidized Al/Si (111) substrates were better than those of the nanostructures synthesized on Si (111) substrates although the nanostructures synthesized on the Al2O3 (0001) substrates were the best.