Background: We report a retrospective study of 47 total prosthesis of hip put in place among the young adult of less than fifty years in the service of Traumatology and Orthopedics at the Wing IV of the CHU Ibn Rochd of Casablanca, over a period from January 2008 to March 2014, with an average rate of decline of 42 months. Results: The deliberate group of 43 patients (47 hips including 4 bilateral) consisted of 26 women, either 60, 47% and 17 men, either 39, 53%. The average age of our patients was 36 years. In our series, the predominant etiology has been conducted for the indication of the hip replacement was the aseptic osteonecrosis of the femoral head which has represented 31.91%. With regards to the choice of implants, 85% of PTH were non-cemented, the cemented PTH has been used in 15% of cases. The Friction Torque metal/polyethylene was used in all cases. The functional outcome was appreciated by the rating of Merle of Aubigne before and after arthroplasty. The average rate of decline of 42 months, and the results were generally satisfactory. They were excellent in 27.78% of cases, very good in 19.44% of cases and good in 44.44% of cases. The results on the Pain were remarkable: the rating of the pain going 2.8 in pre-operative at 5.6 at the latest decline. The results on the walking and mobility were also good. It was noted as a complication: 4 cases of prosthetic dislocation, 1 case of aseptic descellement bipolar, 2 cases of early sepsis on hardware, 3 cases of paralysis of the sciatic external popliteal and 4 cases of periprothetiques ossification. In total, 5 total prosthesis of hip were occasions. The young age does not seem to be an obstacle to the prosthetic surgery. Conclusion: However, a major question remains concerning the distant future of these prostheses in young active subjects, because they will be submitted for many years in a job which can cause the descellement of prosthetic parts.