Authors presented the results of the treatment of osteoarthritis of the hip with MAYO endoprosthesis. The paper is focused on young adults. 34 operations in the 2000-2006 were performed. Cementless MAYO stems were used. 32 patients (24 females and 8 males) were evaluated. The age of patients was 20-54 years (average 32,7 years). The main cause of the hip osteoarthritis was DDH (50%). Among others we identified posttraumatic deformities (14.7%), avascular necrosis of the head, multiepiphyseal dysplasia and the other (35.3%). Cementless press-fit Trilogy cup (Zimmer) was applied in 94.1% and cementless threaded acetabular cup in 5.9% patients. Results were analyzed according to clinical Hip Harris score and radiological assessment. After 7 years follow up good and very good outcomes were found in the majority of patients. Mayo stem causes minor damage of intertrochanteric region during procedure and has minimal effect on medullary cavity. It is an advantage in a case of the migration of endoprosthesis. It preserves the bone stock and allows Total Hip Replacement with cementless stem. Obtained results confirm the value of implantation of this kind of endoprosthesis in the case of young adults. Longer follow up period and bigger group of patients are required to confirm our observations.