A retrospective review of medical records from the Staphylococcus Laboratory, Copenhagen, 1982-1991, was carried out at the Department of Clinical Microbiology, Statens Serum Institut, 1994-1995, to investigate the clinical features and outcome of two subgroups of bacteremic Staphylococcus aureus endocarditis cases in non-drug addicts: patients with prosthetic valve endocarditis (PVE) and patients with native valve endocarditis treated surgically. Twenty-four cases of PVE were included. Six cases were early (within 60 days of valve implantation) and 18 were late. The overall in-hospital mortality was 42%. Surgical treatment resulted in a non-significantly lower mortality as compared with medical treatment alone (0% vs 50%, p = 0.19). Medical treatment of aortic and mitral valve endocarditis resulted in similar mortality rates (44% and 50%, respectively). Twenty-three cases of native valve infective endocarditis had the valve replaced surgically. The in-hospital mortality was 22%, which was significantly lower as compared with medical therapy (69%, p < 0.0001). The treatment changed significantly during the study period: 6 of 112 patients (5%) were treated surgically in the first half of the period (1982-1986) compared to 17 of 124 patients (14%) in the second half (1987-1991, p = 0.049). Severe congestive heart failure was the main indication for cardiac surgery in 21 patients. In conclusion, a shift towards a more aggressive surgical approach has taken place in the 10-year period. This development should be strengthened in the future as surgical intervention may improve survival in patients with infective endocarditis caused by S. aureus whether the infected valve is prosthetic or native.