Sports medicine literature often refers to "swimmer's shoulder." Increasingly, however, it is evident that swimmer's shoulder is a spectrum of maladies whose underlying origins may be incidental to athletic activity. Those dealing with the treatment of swimmers should have a thorough understanding of the differential diagnosis of the shoulder, the age range of competitive swimmers, and the effects of the aging process, and age-related disease processes and should consider the possibilities of neoplasm, degenerative diseases, and acquired processes such as arthritis or metabolic diseases.