Soft x-rays or Grenz rays can be used to form shadowgrams of single textile fibers as well as of yarns and fabrics on fine-grain photographic plates. This paper deals primarily with the microradiography of single fibers and includes a description of experimental equipment, con ditions under which necessary resolution is obtained, impregnation of fibers with substances to increase absorption of x-radiation, and examples of the utility of the method. Single cotton, rayon, wool, and other fibers are clearly resolved by x-radiation generated at 5 kv.; at higher voltages (to 17 kv.), natural fibers give faint shadowgrams. When the fibers are impregnated with 10-20% lead sulfide or other materials, single treated fibers can then be distinguished in masses of untreated fibers. This technique provides a possible means for tracing individual fibers through processing operations.