Achilles tendon disorders are among the more common maladies seen by sports medicine physicians. Understanding the anatomy and biomechanics of the Achilles tendon and contiguous structures is essential to the diagnosis and treatment of Achilles tendon overuse injuries. Posterior heel pain is multifactorial and includes paratenonitis, tendinosis, tendinosis with partial rupture, insertional tendinitis, retrocalcaneal bursitis, and subcutaneous tendo-Achilles bursitis. Each of these entities is distinct, but they often occur in combination. Although most cases of this disorder are successfully treated nonoperatively, a small subgroup of recalcitrant cases may benefit from surgical intervention. Complete ruptures in active, athletic persons should be treated operatively in most cases and result in predictably good outcomes. There may be some cases that escape early recognition and require a reconstructive procedure to salvage a potentially severe functional deficit.