Aim: The early results of cementless femoral components in young patients have been reported, but there are only few reports with more than 10 years follow-up. Methods: We evaluated the clinical and radiographic results of the þrst consecutive 154 implantations of a cementless, double tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47, 13–55) years. Results: After a mean follow-up of 12 (10Ð15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision- 1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. Overall survival was 97% at 12 years (95%-conþdence limits, 93% Ð 100%), survival with femoral revision for aseptic loosening as an end point was 98% (95%-conþdence limits, 95% Ð 100%). The median Harris-Hip-Score at follow-up was 84 points. No thigh pain was found. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2 Ð 6 on anterio-posterior (AP) radiographs. No femoral osteolysis was found. Conclusions: The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However the high rate of cup loosening and the low Harris Hip Scores are concerning in this group of young patients.