During the years 1978 and 1979, the results in 257 patients with a primary anterior dislocation of the shoulder were prospectively studied. The patients were less than forty years old and had been treated at twenty-seven Swedish hospitals. Thirty-two patients had a fracture of the greater tuberosity, but none of them reported having any further dislocations within two years after treatment, while 32 per cent of the patients without this fracture had a redislocation during the same period. The incidence of fractures of the greater tuberosity varied with the age of the patient; the highest rates were in the age groups of twelve to thirteen years and thirty-four to forty years (43 and 30 per cent, respectively), while in the age group of twenty to twenty-two years this injury was found in only 3 per cent of the patients. Chip fractures of the glenoid rim were found in 8 per cent of the patients, most of whom were in the older age groups. Impression fractures in the posterior part of the humeral head were demonstrated in 55 per cent of the patients and were not associated with a significantly higher rate of recurrence of dislocation. One hundred and twelve patients used an immobilization device for three to four weeks, while 104 patients began to use the shoulder as early and as freely as possible. At the two-year follow-up the groups showed an equal rate of recurrence of dislocation. In the age group of twenty-two years or younger nearly 50 per cent of the patients had one or more recurrences, regardless of treatment. In the two older age groups (twenty-three to twenty-nine and thirty to forty years old), the incidence of recurrence was 25 per cent or less.