One hundred and forty shoulders in 115 patients that had a diagnosis of traumatic or atraumatic recurrent anterior, posterior, or multidirectional subluxation were treated with a specific set of muscle-strengthening exercises. Only twelve (16 per cent) of the seventy-four shoulders (sixty-eight patients) that had traumatic subluxation had a good or excellent result from the exercises, compared with fifty-three (80 per cent) of the sixty-six shoulders that had atraumatic subluxation. For this reason, each patient who has instability of the shoulder should be thoroughly evaluated if a successful result from conservative treatment is to be expected. Every effort must be made to identify the etiology of the instability through careful history-taking, physical examination, and radiographic evaluation.