Epicondylitis of the elbow involves pathologic alteration in the musculotendinous origins at the lateral or medial epicondyle. Although commonly referred to as "tennis elbow" when it occurs laterally and "golfer's elbow" when it occurs medially, the condition may in fact be caused by a variety of sports and occupational activities. The accurate diagnosis of these entities requires a thorough understanding of the anatomic, epidemiologic, and pathophysiologic factors. Nonoperative treatment should be tried first in all patients, beginning with an initial phase of rest, ice, nonsteroidal anti-inflammatory agents, and possibly corticosteroid injection. A second phase includes coordinated rehabilitation, consisting of range-of-motion and strengthening exercises and counterforce bracing, as well as technique enhancement and equipment modification if a sport or occupation is causative. Nonoperative treatment has been deemed highly successful, yet the few prospective reports available suggest that symptoms frequently persist or recur. Operative treatment is indicated for debilitating pain that is diagnosed after the exclusion of other pathologic causes for pain and that persists in spite of a well-managed nonoperative regimen spanning a minimum of 6 months. The surgical technique involves excision of the pathologic portion of the tendon, repair of the resulting defect, and reattachment of the origin to the lateral or medial epicondyle. Surgical treatment results in a high degree of subjective relief, although objective strength deficits may persist.