The records of all Olmsted County, Minnesota residents treated for an initial traumatic anterior shoulder dislocation during a ten-year period were reviewed to study the incidence and natural history of this condition. One hundred twenty-four patients had been treated during the study period, and in 116 patients (93.5%) complete follow-up evaluation was available. The overall adjusted incidence of initial traumatic shoulder dislocations was 8.2/100,000 person-years; of all traumatic shoulder dislocations, the rate was at least 11.2/100,000 person-years. Incidence rates were significantly greater for men than for women. There was no urban versus rural difference in incidence or recurrence rates. The authors concluded that shoulder dislocation occurs most frequently in younger male patients and occurs with similar frequency in urban and rural settings. Except for age-related differences in recurrence rates no significant referral bias was found among patients treated at a tertiary care facility as compared with patients from the local community.