Endoprosthesis replacement is the leading surgical procedures among the whole range of procedures performed on hip joint. The optimal position of the acetabular component of prosthesis is an important factor determining the success of the operation. In the Center of Traumatology and Orthopedics of the Burdenko Main Military Clinical Hospital of the Russian Ministry of Defense was developed a hip replacement navigation system. In the given prospective and randomized clinical study acetabular component prosthesis was fixed with the help of "image-free" navigation system (the control group, n=56) and with the help of navigation system developed by the authors (experimental group, n=50). An evaluation of the cup position after the operation was carried out by means of computed tomography of the pelvis. An average value of anteversion in the experimental group was 14 +/- 3 degrees in the control group--13 +/- 4 degrees. The average value of the inclination of the experimental group was 44?5, in the control was 45 +/- 4 degrees. Developed navigation system allows us orienting acetabular component of prosthesis properly, reducing time of surgical procedure and obtaining good and excellent functional results after the surgery.