Clear cell chondrosarcoma of bone, a low-grade malignant tumor, frequently presents diagnostic difficulties. Its clinical, roentgenographic, and pathologic characteristics separate it from conventional chondrosarcoma and, more importantly, from several benign bone tumors with which it is often confused. This report analyzes 47 cases seen at the Mayo Clinic and in consultation. The lesion is more common in males than females (2.6:1) and has a predilection for the end of long bones, particularly the proximal femur. The age range is wide; most patients are in the third and fourth decades of life. Roentgenographically, the lesion most often is purely lytic and slightly expansile, with a sharp margin between the tumor and the adjacent normal bone. Pathologically, clear cells arranged in an indistinct lobular pattern characterize the tumor. Frequently, areas mimicking other primary bone tumors, benign and malignant, are present, often to such an extent as to obscure the true identity of the process. The overall mortality in the present series was 15%. En bloc resection, including a margin of normal bone and soft tissue, appears to be the treatment of choice.