Undisplaced fractures of both the diaphysis and the lateral end of the clavicle have a high rate of union, and the functional outcomes are good after nonoperative treatment. Nonoperative treatment of displaced shaft fractures may be associated with a higher rate of nonunion and functional deficits than previously reported. However, it remains difficult to predict which patients will have these complications. Since a satisfactory functional outcome may be obtained after operative treatment of a clavicular nonunion or malunion, there is currently considerable debate about the benefits of primary operative treatment of these injuries. Displaced lateral-end fractures have a higher risk of nonunion after nonoperative treatment than do shaft fractures. However, nonunion is difficult to predict and may be asymptomatic in elderly individuals. The results of operative treatment are more unpredictable than they are for shaft fractures.