Fifty-two cases of giant cell tumor of bone have been treated by cryosurgery--an extensive freezing of residual tumor after curettage. Cryosurgery is performed by direct pouring of liquid nitrogen into the tumor cavity through a funnel. The cavity is filled with methylmethacrylate and corticocancellous onlay grafts until peripheral bone regeneration occurs to provide bone stability and prevent postoperative pathologic fracture. Patients with lesions in a weight bearing bone are placed in a long leg ischial weight bearing brace until sufficient healing has taken place. Rebiopsy (a second stage diagnostic procedure) is performed 3-6 months after the original cryosurgery. By comparison of pathology, results and complications between our first series of 25 cases and the additional 27, we have observed only one frank malignant giant cell tumor (1.9% incidence). This is much lower than the previously reported 16% fully malignant complication rate, and may be the result of the rapid elimination of the giant cell tumor by cryosurgery.