Internal friction was measured at about 550 Hz in the temperature range between 160 K and 350 K for austenitic stainless steel subjected to hydrogen charging and plastic deformation. A hydrogen-induced characteristic peak was found at 300 K for both annealed and deformed specimens of all the materials used; SUS 310S, SUS 316 and SUS 304. Plastic deformation did not alter its height and shape at all, but brought about two distinct sub-peaks at 330 K and 230 K. The main peak at 300 K is attributable to the Snoek ordering of hydrogen atom-pairs in the FCC alloy steels, being independent of dislocations and other defects produced by plastic deformation. The 330 K sub-peak was observed for all deformed specimens in both cases of prestraining and post-straining. It may be a modified form of the cold work peak, presumably due to the dislocation relaxation associated with hydrogen atmosphere. The 230 K sub-peak was observed only after post-straining of the hydrogen-charged specimen and may be attributed to trapped hydrogen bound tightly to lattice defects.