Twenty patients with total rupture of the achilles tendon were treated by immobilisation in plaster in the gravitation-equinus position for eight weeks. All were healthy persons with a mean age of forty-three years. After removal of the plaster, seven patients had a re-rupture, four of whom were treated by operation, whilst two others sustained a deep vein thrombosis with an associated pulmonary embolus in one case. At follow-up, between 6 and 29 months after the rupture, 16 patients had no complaints and the remaining four had only minor problems. The range of motion in the ankle joint was normal in all patients and the strength in the affected calf was restored to normal in the majority. However, the strength recovered less in those patients with re-rupture who were treated conservatively for the second time. Because of the high complication rate we consider plaster treatment inferior to surgical treatment of Achilles tendon rupture.