Accurate assessment of facial skeletal growth remains a major problem in craniomaxillofacial surgery. Current methods include 1) comparisons of chronologic age with growth histories of the patient and the family, 2) hand-wrist radiographs compared with a standard, and 3) serial cephalometric radiographs. Uptake of technetium-99m methylene diphosphonate into bone is a reflection of current metabolic activity and blood flow. Therefore, scintigraphy with this radiopharmaceutical might serve as a good method of assessing skeletal growth. Thirty-four patients, ranging in age from 15 months to 22 years, who were undergoing skeletal scintigrams for acute pathologic conditions of the extremities, were used to develop standards of uptake based on age and skeletal maturation. The results indicate that skeletal scintigraphy may be useful in evaluation of mandibular growth.