Objectives : The objective of this study is to report the effect of Traditional Korean medical therapy and core exercise on osteoarthritis of knee joint by observing a clinical case study. Methods : Patient with a diagnosis of osteoarthritis of knee joint, was treated by acupuncture, herb medicine, physical theraphy and core exercise. Results : After treatment, Visual Analogue Scale(VAS), Korean version of the Western Ontario and McMaster Universities(KWOMAC), Pain Rating Score(PRS) were reduced from 5 to 2, from 25 to 16, from 55 to 27, and CENTAUR test results were improved. Conclusions : This study showed that Traditional Korean medical therapy and core exercise has meaningful effect on osteoarthritis of knee joint, and more researches should be followed.