In the recent literature, there are only a few hints on spontaneous or postoperative heterotopic ossifications of the Achilles tendon region. The strategies of treatment are different, both conservative and operative. Postoperative calcifications are not mentioned as typical complications in the treatment of Achilles tendon ruptures. We describe the case of a 39 year old male suffering of an increasing, painful swelling and a decrease of loading capacity. In clinical, sonographic and radiological investigations,we found large peritendinous calcifications ventral to the intact heel tendon up to 36 mm in diameter. After operative resection of the calcifications and postoperative chemical prophylaxis, the patient has been without pain for 1 year. There was no relapse of the calcifications or re-rupture of the tendon.