Radial head subluxation is a frequent upper-extremity injury in children. Through a prospective study of patients seen in the emergency department, the epidemiology and treatment were reviewed, and two methods of reduction were compared. During a nine-month period, there were 87 episodes of radial head subluxation in 83 children with six cases in infants 6 months old or younger. A pull mechanism of injury was not identified in 49% of the cases. Girls were seen more often than boys, the left arm was more frequently involved, and the incidence of recurrence was 26.7%. The two reduction methods did not differ significantly in their initial success rate. The presence of a click during a reduction attempt had a positive predictive value of 92% and a negative predictive value of 76%. Most children (76.8%) had return of arm use in less than ten minutes. Slow return of arm use (more than ten minutes) was not associated with delay in reduction but was associated with age of less than 2 years (P less than .001).