The clinical and radiologic features of 16 cases of surgically and pathologically proved juxtacortical chondrosarcoma were analyzed. The main radiographic findings include: (1) A saucerlike or scalloped defect confined to the outer surface of cortex dut to tumor erosion; (2) Localized cortical proliferation and sclerosis; (3) Soft tissue mass and various forms of calcification within the tumor; but without a bony or calcified shell around the tumor mass and (4) sunray and/or laminated periosteal reaction. The origin of this tumor, its histopathology and classification were discussed. A preliminary investigation on the radiated periosteal reaction and its pathological basis was performed.