Operating room teams at three U.S. hospitals are participating in a controlled clinical trial to evaluate the use of a surgical robot in total hip arthroplasty. The robot, called the ROBODOC Surgical Assistant System, precisely prepares the femoral canal for the placement of a “press fit” cementless prosthesis. The Food and Drug Administration (FDA) requires that the robot, as an investigational device, be tested in a controlled clinical trial to demonstrate safety and efficacy. The clinical trial will include 300 patients who must meet specific criteria before enrollment and randomization. This article describes the need for new surgical technology, ROBODOC's development history hardware and software components of the system, the patient population and surgical protocol for the clinical trial, special nursing care requirements, and considerations for patient rehabilitation.