Background Prosthetic aortic valve endocarditis is a serious complication that carries a high morbidity and mortality.Aortic homografts have been used in this setting, but long- term results are not available.Methods and Results Over a 23-year period, 48 patients presented with infected aortic valve substitutes: 28 homografts, 15 mechanical, and 5 xenografts. Nineteen patients had emergency surgery, and the mean interval between the first and second operation was 5.9 years (range, 1 month to 22 years). In 28 patients, the preoperative New York Heart Association (NYHA) class was III or IV. Active endocarditis was present in 39 patients, and the microorganisms grown were Staphylococcus epidermidis (n=13), Staphylococcus aureus (n=6), Streptococcus viridans (n=6), Streptococcus faecalis (n=4), Candida albicans (n=5), and Gram-negative spp (n=2). Aortic root abscesses were found in 28 (58%) patients, and transesophageal echocardiography was 95% accurate in their localization. All patients received homograft aortic valves, 19 as root replacement and 29 using the freehand technique. There were four (8.3%) early deaths; poor left ventricular function and concomitant procedure were identified as risk factors. At a mean follow-up of 4 years (range, 2 months to 19 years) 95% of the patients were in NYHA class I or II without significant aortic regurgitation. The actuarial survival at 5 years was 97% (confidence limit, 84% to 100%), and freedom from endocarditis at 10 years was 97% (confidence limit, 84% to 100%). Multivariate analysis did not identify risk factors for these late events.Conclusions Homograft aortic valves offer good early and long-term results in patients with infected aortic valve substitutes. (Circulation. 1994;90(part 2):II-198-II-204.)