To determine the frequency with which fractures are encountered in emergency care and to estimate the incidence of fractures in a well-defined population, a population-based sample of emergency department (ED) visits was examined. Eleven percent of ED visits for trauma involved fractures. The incidence of fractures was 21 per 1,000 persons per year and had two peaks, the first at ages 10 to 14 and the second at ages greater than 60. Among young people, falls (often related to sports or recreation), striking objects, motor vehicle injuries, and assaults were the major causes of fractures. Among the elderly, falls caused 87% of all fractures.