Radiosynovectomy has been used as an effective treatment in patients with resistant synovitis after failure of long-term medication and intraarticular steroid injection. Although $^{90}Y$ silicate/citrate, $^{186}Re$ sulfide, and $^{169}Er$ citrate were approved in Europe for the appropriate radiopharmaceuticals for radiosynovectomy other radionuclides such as $^{32}P$-chromic phosphate, $^{165}Dy$-ferric hydroxide macroaggregate, $^{188}Rh$-microspheres, $^{153}Sm-particulate, and $^{166}Ho$-ferric hydroxide macroaggregate have been used in many countries. Reported success rates range from 40% to 90% for the different joints and underlying disease. In Korea, $^{188}Re$-tin-colloid and $^{166}Ho$-chitosan complex are now using as the major radionuclides in radiosynovectomy with good clinical results. A study on radiation synovectomy using $^{188}Re$-tin-colloid for patients with Korean rheumatoid arthritis shows the treatment resulted in the improvement of arthritis and well tolerated in our study, the radiosynovectomy with $^{166}Ho$-chitosan complex in 53 hemophilic patients markedly decreased intra-articular bleeding frequency and need for coagulation factor. This review inculdes general priciples in the application of radiosynovectomy and the clinical experience in Korea.