Monodisperse silver nanowires with high aspect ratio are prepared via electrochemical plating into monodomain porous alumina templates. The nanowires have a length of 30 μm or more, adjustable uniform diameters ranging between 180 and 400 nm, and a monodispersity of about 2%. The templates were fabricated by anodization of imprinted aluminum with an interpore distance of 500 nm. Nearly 100% pore filling was obtained due to a thinning process which guaranteed a barrier layer of homogeneous thickness of a few nanometers. Moreover, hierarchically ordered porous alumina with about 25-nm−40-nm pore diameter on one side and 180-nm pore diameter on the other side was successfully infiltrated by the same method, yielding branched silver nanowires.