Five hundred sixty-four Rochester, Minnesota, residents had a total of 586 humeral fractures during the period from 1965 to 1974. Of these, 47% involved the proximal humerus, and 20% the humeral shaft, and 33% the distal humerus. The incidence of humeral fractures associated with severe trauma was relatively higher among children and young adults, and distal humeral fractures predominated. Among the elderly, however, proximal humeral fractures associated with moderate trauma were most common and were responsible for the excess humeral fracture incidence rates among women and the dramatic increase in rates with age for both sexes. Rochester incidence rates for all three humeral fracture sites were substantially greater than those previously reported from the United Kingdom, although the proximal humeral fracture incidence was very similar to that in Malmo, Sweden. The Rochester rates appear to be the best available for use in determining the costs and benefits of efforts to prevent these and other aging or osteoporosis-related fractures in the United States.