We have described the instrumentation and surgical technique of a new total knee prosthesis, the Total-Condylar, designed at the Hospital for Special Surgery (New York) and which we are the first to use in Italy. This prosthesis has evolved from the "sliding" prosthesis and seems to us to constitute a real step forward. The femoro-patellar compartment is completely substituted. The cruciate ligaments are removed, which markedly increases the possibility of correcting even severe deformities. The fixation of the tibial component is improved by the adoption of a short stem. The prosthesis has a certain intrinsic stability on weightbearing. The surgical technique is characterised by bone sections perpendicular to each other by the use of aligning instruments which simplify the operation. Our experience is just beginning (five cases) but our results so far are very encouraging and correspond to those reported in a very much larger series in the United States.