Background: Extracorporeal shockwave therapy has been shown to be effective in the treatment of chronic tendon pathology in the elbow, shoulder, and plantar fascia. This prospective study examines the efficacy of extracorporeal shockwave therapy in the treatment of chronic Achilles tendon disorders. Methods: Twenty-three patients (23 feet) were treated with extracorporeal shockwave therapy for Achilles tendinosis, insertional tendonitis, or both. Indications for treatment were a minimum of 6 months of conservative care, and a visual analog pain score > 5. The mean follow-up was 20 months (range, 4–35 months). Results: Ninety-one percent (14 patients) were satisfied or very satisfied (23 patients) with treatment. Eighty-seven percent (20 patients) stated that extracorporeal shockwave therapy improved their condition, 13% (3 patients) said it did not affect the condition, and none stated that it made them worse. Eighty-seven percent (20 patients) stated they would have the procedure again if given the choice. Four months after extracorporeal shockwave therapy, the mean visual analog score for morning pain decreased from 7.0 to 2.3, and activity pain decreased from 8.1 to 3.1. Conclusion: High-power extracorporeal shockwave therapy is safe, noninvasive, and effective, and it has a role in the treatment of chronic Achilles tendinopathy. (J Am Podiatr Med Assoc 98(6): 466–468, 2008)