The Swedish Hip Register was initiated in 1979. The mission of the register is to improve the outcome of THA. The hypothesis is that feedback of data stimulates participating clinics to reflect and improve. In addition to revision surgery, patient-based outcome measures and radiographic results are included to improve sensitivity. All patients who have a total hip arthroplasty answer a questionnaire preoperatively and again after 1, 6, and 10 years postoperatively. The questionnaire includes the Charnley classification, EQ-5D and visual analog scales concerning pain and overall satisfaction and is used by 31 of 81 units. Average costs for the procedure ($11,000) are obtained from a national database. The mean gain in the EQ-5D index after 1 year for 3900 patients was 0.37, giving a low cost of $3000 per quality adjusted life year. Patient satisfaction and pain amelioration generally was high. The national average 7-year survival (revision as endpoint), has improved from 93.5% (+/- 0.15) to 95.8 (+/- 0.15) between the two periods 1979 to 1991 and 1992 to 2003. National implant registers define the epidemiology of primary and revision surgery. In conjunction with individual subjective patient data and radiography they contribute to development of evidence-based THA surgery.