The classic position of immobilization of Colles' fractures with the elbow in flexion, the forearm in pronation, and the wrist in volar flexion and ulnar deviation is probably the main reason for the common and rapid recurrence of the original deformity. Such a position places the brachioradialis muscle, a strong flexor of the elbow and the only muscle attached to the distal fracture fragment, in an ideal physiological position to exert a deforming force on the fracture fragments. Based on this assumption, further supported by electromyographic studies, a method of treatment was developed which calls for the initial immobilization of the arm in an above-the-elbow cast with the elbow in flexion, the forearm in supination, and the wrist inmoderate ulnar and volar flexion. This cast is changed a few days after application for an Orthoplast brace that permits motion of the elbow and volar flexion of the wrist while preventing pronation and supination of the forearm and dorsiflexion of the wrist. The proposed method did not prevent collapse of the fragments in all instances. However, the degree of collapse was minimum. The position of supination of the forearm and the freedom of motion of all joints seemed to reduce the swelling, stiffness, and incapacitation frequently found during active treatment of these fractures.