Fractures and epiphyseal injuries in the region of the elbow are uncommon in infants and young children, but they can be very difficult to diagnose and delineate accurately. In addition to plain radiography, invasive or costly procedures such as arthrography and magnetic resonance imaging traditionally have been used to evaluate these injuries. We used high-resolution real-time ultrasonography to evaluate a suspected injury of the elbow in seven infants and one ten-year-old child. Three of the infants had a physeal separation, two had a supracondylar fracture, and two had no skeletal injury. The child had an avulsion fracture of the lateral epicondyle of the humerus and an effusion in the joint. The ultrasonographic findings were confirmed by arthrography in three patients, by open reduction in one, and by follow-up radiographs in all. None of the ultrasonographic studies were performed with the patient under general anesthesia. Ultrasonography, a readily available, non-invasive technique, can be used to evaluate the unossified epiphysis about the elbow of infants and young children; to demonstrate dislocations, fractures, and physeal separations; to identify a hinge of soft tissue at the site of a fracture; to identify interposition of soft tissue between fracture fragments; and to aid in the planning of closed and open reductions.