During the period of 5 years and 5 months, from January 1979 to May 1984, we treated 27 cases(17 patients) of osteoarthritis with genu varum deformity by high tibial osteotomy. The results were as follows: l. In the 27 cases of the high tibial osteotomy, 24 cases were female and 3 cases were male. 2. Of the etiology of the osteoarthritis with genu varum, 14 female patients had primary one and 3 male patient knees were related with infection(2 patients) and trauma (1 patient). 3. Preoperative varus angles, ranging from 0° to 20°, 6.4° in an average and postoperative valgus angles, ranging from 5° to 15°, 8° in an averge. 4. In a review of the high tibial osteotomy, good and fair results were noted in 26 cases (96.3%) of the knees after average 2 years of follow-up. 5. The high tibial osteotomy is found to be useful method in the treatrnent of the osteoarthritic knee with varus deformity.