The precise metallization of double-stranded DNA by the selective electroless plating method was investigated for the purpose of the fabrication of nanowires. Cis-platin was bound to template DNA molecules and reduced to platinum which can catalyze following silver metal deposition. The DNA molecules combined with the platinum clusters was stretched and immobilized on a glass substrate by using the LB method. The electroless plating of the platinum-bound DNA molecules immobilized on the substrate by reduction of silver ion gave uniform silver nanowires (ca. 30 nm height and 50 similar to 100 nm width) along the stretched DNA structures. On the contrary, the electroless plating of DNA molecules without the catalyst provided inhomogeneous silver deposition. Conductive AFM measurement revealed that the obtained silver nanowires as long as several mu m had high conductivities.