The Novacor left ventricular assist system (Baxter Healthcare Corp., Novacor Div., Oakland, Calif.) is currently undergoing clinical investigation as a bridge to cardiac transplantation. The original animal and clinical protocols recommended placement of the pump/energy converter within the peritoneal space. During preclinical cadaver fitting trials, we determined that it might be difficult to place this device in the peritoneal cavity of tall, slender patients, patients having a small muscular abdomen, and many women. We were also concerned that peritoneal placement would increase the risk and severity of infection and that abdominal organs might be injured by direct contact with the pump. In studies in cadavers, we therefore developed a technique using preperitoneal placement of the pump/energy converter. This technique has now been used successfully in more than 200 patients. A detailed description of this insertion technique is presented to facilitate its current use for the implantation of temporary devices and to plan for the implantation of permanent systems.