The authours reviewed 9 cases of giant cell tumors around the knee joint which were treated by curettage and barium sulphate mixed cementation at Catholic Medical Center, between Jaunary 1979 and December 1983. Among the 9 patients, 7 patients could be followed more than 2 years, ranging from 24 months to 42 months, averaging 31 months. The result obtained were as follows; 1. No local recurrence or distant metastasis have been observed among these 7 cases. 2. Radiological assesment of the lesion after radiopaque cementation is believed to be a good method for detecting local recurrence. 3. Filling the curetted cavity with bone cement permits early joint mobility and weight bearing. Curettage and bone cementation may turn out to be the mothod of choice for the giant cell tumor located at the very end of the weight bearing joint when a simple curettage or resection is no longer possible without loss of function. Also it is suggested that the heat generation during polymerization of the bone cement and cytotoxic effect of non-polymerized monomer might have some cidal effect on the tumor cell.