Aims: The purpose of this study was to evaluate results of uncemented THA done with self-threaded cup, in young patients. Methods: 123 patients with uncemented self-threaded cup (MECRING) were followed minimum 5 and maximum 10 years. They were radiographically and clinically evaluated in order to see the incidence of aseptic loosening of the cup. A deþnite aseptic loosening of the cup was diagnosed when there were radiolucent lines wider than 2 mm in two of three zones around the cup with or without migration, followed with low Harris Hip Score (start-up or weight-bearing pain, limping, use of cane or crutches). Results: 12 patients (9,76%) had deþnite aseptic loosening and have been revised. All of them were very young at the time of their primary THA (preoperative diagnosis being either post-traumatic arthritis or developmental dysplasia of the hip). Conclusions: Uncemented self-threaded cup has a high incidence of aseptic loosening and high revision rate. It should be completely replaced with uncemented, porous-coated, press-þt cup with screw þxation, especially in young patients.