We have prepared samples of Zn wire structures by electrochemical anodization and measured their photoluminescence spectra at various temperatures. Scanning electron micrographs (SEM) were also taken on these samples. It was found that the dimension of the Zn wires has a definite influence on the photoluminescence (PL) spectra. Specifically, large wire dimensions exhibit a blue/violet luminescence. In addition to this blue/violet luminescence, nanowires of Zn about 20 nm in diameter exhibit a PL peak at 379 nm, which is the characteristic of ZnO. Low-temperature PL measurements on these Zn nanowires reveal three distinct excitonic emission peaks similar to high-quality ZnO. These results strongly suggest that high-quality ZnO nanowires can be formed by electrochemical etching of Zn.