Abstract: The use of thermally insulated bodies is determined by their insulative properties, on the one hand, and by the economy of their fabrication on the other hand. A particularly simple method for manufacturing a thermally insulated body, e.g. a pipe, with inner and outer shells, especially with metallic inner and outer shells, forming an intermediate space which is filled with porous particulate and/or porous powdered insulating material, evacuated and hermetically sealed consists in first evacuating the intermediate space between the inner and outer shell, maintaining the space under vacuum and then introducing the insulating material from a reservoir maintained under vacuum and sealing the intermediate space.