With a clinical goniometer, we measured the arcs of active motion of the shoulder, elbow, forearm, wrist, hip, knee, ankle, and foot in 109 normal male subjects ranging in age from eighteen months to fifty-four years old. The normal limits were determined for subjects who were one to nineteen years old and for those who were twenty to fifty-four years old. Significant differences were found between the two age groups for most motions. The data were compared with estimations in the handbook of The American Academy of Orthopaedic Surgeons as the standard reference. The data constitute a more detailed set of measurements, based on a sample described according to height and age, than has been available hitherto.