Surgical therapy of native infective endocarditis is still considered as a particular challenge, due to remaining morbidity and mortality up to 20%. Further risk analysis and characterization of clinical features is of great importance for further improvement of surgical results. The aim of this retrospective study was a risk analysis concerning clinical features of the pre-, intra- and postoperative period. Between 02/1997 and 12/2003, 165 patients (130 male, 35 female, age 55.5 +/- 13.8 years) were referred for surgical therapy of infective endocarditis at our institution. Preoperative, intraoperative and postoperative features were evaluated for their influence on the early postoperative course and the mid-term follow-up. In the majority of patients (pts) the aortic valve was infected (n = 83, 50.3% of pts), followed by mitral valve (n = 33; 20.0%), tricuspid valve (n = 10, 6.0%) and pulmonary valve (n = 2; 1.2%). Double valve affection was recorded in 37 pts (22.4%). Streptococci (n = 66, 40.0%) and staphylococci (n = 66, 40.0%) were the most common pathogens. The overall hospital mortality rate was 10.9% (n = 18), during follow-up (mean follow-up 3.3 +/- 2.5 years) a further 20 pts (12.1%) died.Main predictors for hospital mortality in multivariate analysis were older age (p = 0.01), prolonged ICU stay, prolonged intubation (p = 0.03; p = 0.02) and the continuous postoperative need of alpha-catecholamine medication (p < 0.01). Significant predictors of overall mortality were older age (> 70 years) and diabetes (p = 0.03; p = 0.03). Reinfection occurred in 6.1% of patients (n = 10). Actuarial freedom from recurrent infection was 97% at 1 year and 93.9% at 5 years. Surgical therapy of infective endocarditis is associated with good clinical results in the early and mid-term follow-up. Predictors of outcome particular include preoperative risk constellation or comorbidity (age, diabetes) and variables of the immediate postoperative course.