Hollow and solid cylindrical nanometric structures of mixed valent manganese oxide-based compounds were obtained by wetting sacrificial porous substrates. Plastic templates with pores ranging 0.05-1 µm were employed; a two-stage thermal process was performed to obtain La_0.325Pr_0.300Ca_0.375MnO₃ or La_2/3Sr_1/3MnO₃. Polycrystalline self-standing tubes were obtained for pore size higher than 0.2 µm, while wires were obtained for diameters below 0.1 µm. We discuss the role of the template pore size in determining the synthesis route, the formation of different intermediate compounds, and different morphologies.