Alkaptonuria is a hereditary disorder of phenylalanine and tyrosine, with an incidence of approximately 1/200,000 to 1/1,000,000. Ochronosis is the accumulation of homogentisic acid and its metabolites in connective tissues such as the tendons, cartilage, and skin. In the present case study, a 50-year-old male presented with a nontraumatic calcaneal avulsion without a previous diagnosis of ochronosis. To the best of our knowledge, little information has been reported of this pathology in the Achilles tendon and the surgical management. (C) 2017 by the American College of Foot and Ankle Surgeons. All rights reserved.