Benign osteoblastoma is a rare tumor, more frequent in males, usually occurring in patients under the age of 30 years, and is seen most frequently in the spine, femur, tibia, and mandible. Its varied roentgenographic appearance may suggest a large osteoid osteoma or an aneurysmal bone cyst, but about one-fourth of cases present a picture consistent with a malignant neoplasm. The roentgen changes in the spine are frequently subtle and require care for identification. Differentiation from osteogenic sarcoma is sometimes difficult even with histological material, because some low grade osteogenic sarcomas contain areas resembling osteoblastoma. Conservative surgery is the treatment of choice for osteoblastoma.