We clinically evaluated 36 competitive swimmers who had shoulder pain; the majority were women. Twenty-three swimmers had unilateral shoulder pain and 13 had bilateral pain, making a total of 49 painful shoulders. Shoulder pain had been present significantly longer in swimmers with bilateral shoulder pain (mean, 104 weeks) than in swimmers with unilateral pain (mean, 33 weeks). Twelve shoulders exhibited signs of impingement without excessive humeral head translation. In 25 shoulders, concomitant signs of impingement and increased glenohumeral translation, together with a positive apprehension sign, were found. Four swimmers, who were generally joint hypermobile, exhibited bilateral impingement signs and excessive humeral head translation, most commonly in the anteroinferior direction. Four shoulders had excessive humeral head translation and apprehension without impingement. Lack of coordination in the scapulohumeral joint was seen significantly more often in symptomatic than in asymptomatic shoulders. Hawkin's test for impingement was more sensitive than Neer's test. Swimmers with shoulder pain have variable clinical findings. The majority demonstrate signs of impingement and increased humeral head translation in the anteroinferior direction together with a positive apprehension sign. This nontraumatic instability might result from wearing of the anteroinferior capsuloligamentous complex. The different clinical findings might represent different stages of the same condition.