Abstract: Structurally ordered nano self-assemblies of protein can be useful for the fabrication of nano-devices. In the present study, we have developed a technique to construct a mold from a nanometer-sized protein self-assembly. As a template, myosin filament was prepared from monomeric myosin by dialysis against a low ionic strength aqueous solution. The myosin filament was adsorbed on the surface of a glass substrate and its imprints were developed on the Ni mold surface (Fig. a). The mean dimension of the filamentous structures developed on the Ni mold surface was 1670 x 150 x 5 nm3, being consistent with that of myosin filaments on the original substrate. Furthermore, it was shown that the pattern developed on the Ni mold was successfully transferred to a poly (methyl methacrylate) surface (Fig. b). Thus, it is indicated that the property of some proteins to form organized structures like self-assemblies and crystals should be applicable to the fabrication of devices on which ordered nanometer-sized structures are formed. Moreover, the present technique should be extensively applied to the fabrication of nano-devices such as quantum dots, photonic crystals and so on.