The socket is considered an element of major importance in the makeup of a prosthesis. Each socket is a tailor-made device, designed to fit the unique geometry of the patient's residual limb. The design and manufacture of a prosthetic socket traditionally has been a manual process that relies on the use of plaster of Paris casts to capture the shape of the patient's residual limb and then artisan fabrication techniques to manufacture the socket. Computer-aided design and manufacturing technologies have overcome some of the shortcomings of the traditional process, but the final manufacture of the prosthetic socket is still performed manually. Rapid prototyping (RP), a relatively new class of manufacturing technologies, creates physical models directly from three-dimensional (3-D) computer data. Previous research into the application of RP systems to the manufacture of prosthetic sockets has focused on expensive, high-end technologies that have proven too expensive. This paper investigates the use of a cheaper, lowend RP technology known as 3-D printing. Our investigation was an initial approach to using a technology that is normally associated with producing prototypes quickly, some of which could not be manufactured by alternative means. Under normal circumstances, these printed components are weak and relatively fragile. However, comfortable prosthetic sockets manufactured with 3-D printing have been used in preliminary fittings with patients.Abbreviations: CAD/CAM = computer-aided design and manufacturing, CNC = computer numerically controlled, FDM = fused deposition modeling, PU = polyurethane, RDM = Rapid Design and Manufacture, RMM = Rapid Manufacturing Machine, RP = rapid prototyping, SLS = selective laser sintering, 3-D = three-dimensional, 3DP = 3-D printing, UV = ultraviolet.