This paper presents a new method for conceptual design which is suited to mechanical design problems with complex forms such as machine design. The backwards design method involves starting with an idealistic semi-working solution and then systematically solving the unworkable parts of the solution until a complete solution is found. The method has the advantage that it gives the designer a good starting point in the conceptual design process. The method also exploits the principle that it is easier to critique and modify than it is to create something out of nothing. Three case studies of machine design that were carried out using the backward design method are presented. The case studies involve a novel clutch, a novel rotary damping mechanism and a novel worm gearbox. Each of these machines won at least one national design competition in the UK.