Recently, transition-metal-doped semiconductor nanostructures, so-called diluted magnetic semiconductors, such as dots, rods, wires, and films, have been the subject of intense research efforts due to their fascinating properties and potential applications in bioimaging, spintronics, and quantum interference information processing. Here, we present a method for synthesizing superdiluted Ni-doped ferromagnetic silicon nanotubes (SiNTs) (with room-temperature ferromagnetism), with minimal synthetic steps and with maximal control of the resultant SiNTs structure and composition. The unique advantage of our approach is the simplicity that provides us precise control of the ferromagnetic SiNT parameters, length, outer and inner diameter, wall thickness, Ni concentration, and crystallinity, by changing the template membrane (pore diameter), dipping time in the catalyst, growth time, and decomposition temperature. Numerous combinations of SiNT parameters can therefore be prepared that can influence their magnetic and electronic properties. This level of control can lead to novel future nanoelectronic and nanospintronic devices.