Forty-one patients with infective endocarditis were treated surgically at the University of Alberta Hospital, Edmonton, between 1961 and 1980. Their ages ranged from 10 to 67 years and the male to female ratio was 4:1. A wide variety of organisms were cultured but gram-positive organisms predominated. Bicuspid aortic valves, normal valves and valves affected by rheumatic heart disease, were the most common sites of infection. The aortic valve was most frequently involved. The onset of left ventricular failure was the major indication for surgery. The overall mortality at 30 days was 19.5%. The mortality after 30 days was 9.8%. Eleven of 12 patients who died had left ventricular failure preoperatively. The mortality in patients who had valve replacement during the first 4 weeks of infection did not differ from those who had valve replacement after 4 weeks of infection. Hemodynamic studies following operation in six patients showed that pulmonary arterial and wedge pressures had returned to normal levels. Nineteen of 26 patients who were followed up were asymptomatic. One had a malfunctioning prosthesis, one chronic heart failure and one had reoperation for paravalvular leak. Four patients diet during the follow-up period. The authors conclude that all patients with infective endocarditis who suffer left ventricular failure should have prompt valve replacement regardless of the duration of antibiotic therapy.