We analyzed the complications after surgical treatment of Achilles tendon overuse injuries in 432 consecutive patients. The patients underwent a clinical examination 2 weeks, and 1, 2, and 5 months after the surgery. If a complication appeared, the patient was followed up clinically for at least 1 year. There were 46 (11%) complications in the 432 patients: 14 skin edge necroses, 11 superficial wound infections, 5 seroma formations, 5 hematomas, 5 fibrotic reactions or scar formations, 4 sural nerve irritations, 1 new partial rupture, and 1 deep vein thrombosis. Fourteen patients with a complication had reoperations: four patients for skin edge necrosis, two for superficial wound infection, two for seroma formation, one for hematoma formation, two for fibrotic reaction or scar formation, two for sural nerve irritation, and one for a new partial rupture. About every 10th patient treated surgically for chronic Achilles tendon overuse injury suffered from a postoperative complication that clearly delayed recovery. However, the majority of patients with a complication healed and returned to their preinjury levels of activity. To reduce this morbidity, it is essential that the surgeon be continuously aware of the possibility of postoperative complications and use proper surgical techniques.