Rheumatoid arthritis, thought incurable for many years, was treated by radioactive hot spring bath and uranium deposit clay at Ningyo-pass. The therapeutic effects of balneotherapy and "Fango" were stUdied comparatively. Results of hot spring bath for one month were effective in 63 of 73 cases (86.3 per cent), and 60 per cent even in (222) chr., in which attaind Grade III. It was thought that therapeutic effect of bathing on (222) chr. was increased using together with adrenocortical hormone. Uranium deposit clay at Ningyo-pass was used on 59 cases of this disease, in form of "Fango" and local bath in mud. It was effective in 60.8 per cent of 171 joints, and in 53.4 per cent of 131 joints of (222) chr. It showed that this was valuable as a local therapy for those incurable types of the disease.