Background. Authors introduced a case of a 27-year men with osteopetrosis with hip arthrosis. He has an autosomal – dominant form of disease and he needed total hip arthroplasty. There are seven cases described in literature with developed hip arthrosis by osteopetrosis. Methods. TEP implantation represents the greates surgical challenge in this patients, especially creation of intramedullary canal in femur and implantation of the femoral stem because of the very dense and brittle bones. This article describes the operative technique used in the case involved. It proved to be a very good solution. Results. The patient was released from the hospital ten days after implantation of total hip endoprosthesis. Three months after the operation the patient started to walk without aid of canes, he had non pain, and his range of motion was almost normal. Conclusions. Severe coxarthrosis is a rare complication of osteopetrosis. Great care must be taken with implantation of total hip endoprosthesis, especially with preparation of medular canal. It was recommended hand drilling under x-rays to exercise maximal control because reaming can cause false root of stem and greater probability of fracture.