Aim: The goal was to analyze hip joint by RTG before and after the surgery and to find out the real difference in leg length as well as to determine the position of the femoral part of endoprosthesis. Material and methods: 40 patients had implanted noncement endoprosthesis and another 40 cement endoprosthesis. Data were calculated for the period from 1.1.2007. to 31.12.2008., retrospectively. Results: In our research, upon implanting noncement prosthesis 26 of examined patients had longer leg after the procedure, but none had the deviations larger than 2 centimeters. Furthermore, 4 had shorter leg, and 10 had equal leg length before and after the surgery. 92 % of all patients had Intraplant type endoprosthesis implanted and remaining 8 % had Zimmer type endoprosthesis. Intraplant endoprosthesis were mostly implanted in valgus position – 18 cases, 10 were implanted in varus position and 9 in neutral position. In Zimmer case however 2 endoprosthesis were implanted in valgus position and 1 in neutral position. In case of cement endoprosthesis implantation 34 of patients had on leg longer, two of them deviation more than 2 cm. One patient had shorter leg and in 5 cases the length of leg were not changed before and after the surgery. 75 % of all patients had implanted Surgival endoprosthesis and 21,5 % of them had Zimmer and ZweiMuller endoprosthesis. 50 % of Surgival endoprosthesis were implanted in valgus position of phemoral part, 30 % in neutral position and remaining 20 % in varus position. In Zimmer case 50 % of all endoprosthesis were implanted I neutral position of femoral component. Conclusion: One of main goals of total hip arthroplasty is a complete reconstruction of normal hip biomechanics which influence longevity of endoprosthesis. Leg length discrepancy is one of the potential complications after total hip arthroplasty that can affect patient satisfaction with the operation. Although, sometimes it is not possible to fully reconstruct the normal hip biomechanics, proper preoperative preparation, and appropriate positioning of femoral components can significantly affect the leg length discrepancy.