We have prepared hexagonally arranged pore arrays with large interpore distance (200-460 nm) by using two kinds of techniques: a self-organization process and a prepattern guided anodization on aluminum. The self-organized pore arrays were produced by anodizing aluminum in an aqueous phosphoric acid solution (H3PO4:CH3OH:H2O = 1:10.89), and show a polycrystalline, i.e., poly-domain, feature. Within each domain of several micrometers, the arrays are hexagonally arranged with an interpore distance of 460 nm, while the domains are oriented randomly in plane. A monocrystalline pore array structure with variable interpore distance was prepared based on electron-beam lithography and a subsequent anodization in oxalic acid solution. With a well-designed set of anodization parameters, the prepattern can act as the initiation points and guide the pore growth in the anodic film. Very high aspect ratios (similar to 500) can be achieved.