Arrays of ideally ordered alumina nanochannels with unprecedented similar to 10 nm pore size, 40-50 nm interpore spacing, and improved channel uniformity have been fabricated by anodizing an aluminum substrate with a guiding pattern on its surface. The pattern is an array of hexagonally close-packed concaves fabricated by focused ion beam direct sputtering; and its lattice constant is carefully matched to the conditions of the subsequent anodization process in order to achieve effective guiding in the growth of the nanochannels and therefore the ordering of an, array. (c) 2005 American Vacuum Society.