A programme for early mobilisation using a temporary prosthesis was evaluated in 17 children who had had an amputation above the knee for sarcomata. The temporary prosthesis had a performed adjustable polypropylene quadrilateral socket which was able to accommodate changes in the size of the stump during the first few months after amputation. The adjustable sockets were assembled onto wooden knee-shank-foot units or onto modular components covered with foam. The wooden units were better for routine use as more adjustment was possible between the socket and the knee and because they were more durable in active children. Prosthetic fitting usually took one hour and was carried out 10 days after the amputation to coincide with the start of the chemotherapy programme. The prosthesis was cosmetically acceptable, easy to use and provided a simple and economical way of rehabilitating the amputees and restoring their morale. After two to three months a new prosthesis with a laminated socket suspended by a waistband was supplied. The skin tolerated the closer fit of this socket and the small fluctuations in the size of the stump that occurred with each course of chemotherapy were easily accommodated by varying the thickness of the stump sock. A self-suspending laminated socket was provided after completion of the chemotherapy. The permanent sockets were assembled onto wooden components but the girls usually preferred the modular system covered with foam. The chemotherapy and rehabilitation programmes were successfully co-ordinated so that the children spent as little time as possible away from their normal activities.