Highly ordered arrays of parallel cobalt disulfide nanowires with a diameter of about 40 nm and a length up to several tens of micrometers were synthesized by two electrical fields in an anodized aluminum oxide film. The cobalt disulfide nanowires have a cubic pyrite structure. In the study of electrochemical properties, it is found that the reaction of cobalt disulfide is an intercalation reaction in the range of 1.6-3.0 V, while a redox reaction in the range of 0.02-1.6 V is probable. The CoS2 nanowires are ferromagnetic and the easy magnetization direction is along the nanowire axes. (c) 2007 The Electrochemical Society.