Summary: To determine the effects of limb positioning on Baumann's angle, we made a controlled radiographic study of a 6–year-old cadaver upper extremity specimen. Radiographic measurement of Baumann's angle was obtained at 10° increments of humeral rotation from 40° of internal rotation to 40° of external rotation. These measurements were obtained with the humerus parallel to the x-ray cassette and with the humerus flexed 30° from the cassette. Measurement of Baumann's angle with radiographs obtained with the humerus parallel to the x-ray cassette was associated with less variation in the measured angle (6° of change for every 10° of rotation). The relevance of these findings in management of supracondylar fractures is discussed.