The invention relates to a method of producing nanotubes from coaxial jets of immiscible liquids or poorly-miscible liquids. The purpose of the invention is to produce hollow fibers (nanotubes) or composite fibers having diameters ranging from a few micras to tens of nanometers and comprising walls, in the case of nanotubes, with a thickness ranging from hundreds of nanometers to a few nanometers. The inventive nanotube-formation method involves the generation of coaxial nanojets of two liquids using electrohydrodynamic technology.