Polystyrene-block-poly(methyl methacrylate) nanorods were prepared by wetting ordered porous alumina templates. We systematically investigated the diameter-dependence of their morphologies by varying the pore diameters of the templates from 400 nm down to 25 nm. If the pore diameter exceeds the period of the block copolymer, the pores accommodate a non-integer number of repeat periods. In case of smaller pores the occurrence of an ordered state could not be unambiguously verified.