Haglund's disease, an inflammation of the retrocalcaneal bursa and a bone enlargement on the back of the heel, is a painful syndrome mainly caused by the exostotic prominence of the posterior calcaneus. Conventional treatment consists of rest, shoewear modification, medical therapy and, in selected cases, surgery. We report the case of a 59-year-old male with a history of severe atraumatic monolateral heel pain treated with foot orthotics, rest and surgery with partial regression of symptoms. Owing to the persistent heel pain and physical impairment after surgery, the patient underwent radiotherapy, which was successful in relieving his symptoms.