The advantages of plastics are well known, but there are still some who maintain that these materials are costly and difficult to manipulate. It is not usually remembered, however, that plastics already have their place in orthopaedic splint manufacture, for example in celluloid appliances of many kinds which are in everyday use. They are much lighter than plaster of Paris; they are unaffected by water and body secretions; and some are radiolucent. With the rapid development of modern plastics now taking place there is a wide field for research into their application in orthopaedic surgery. In describing a range of plastic splints and appliances, and outlining the details of their construction, we have tried to show that such research is worth while.