The study makes an assessment of the results of surgical treatment of infectious endocarditis in 25 patients operated in 1982-1988 at the Institute of Experimental and Clinical Medicine. At the active stage of the disease, surgery was performed on 15 patients (60%), while prior to the operation, 16 persons' condition (64%) corresponded to the IIIrd and IVth degree of the NYHA functional classification. In infectious endocarditis, early mortality after valve replacement was 8%, late mortality--9% with an average of two-year post operative follow-up. Re-infection occurred in 12% patients, paravalvular regurgitation was found in 20 percento, out of whom 8% were haemodynamically significant and associated with the infection. Clinical post-operative improvement was observed in 76% patients, out of whom one half was totally asymptomatic and one third resumed their jobs. The results show that early surgical treatment of infectious endocarditis helps to reduce mortality. The post-operative risk of re-infection or of other complications was not high and the long-term post-operative functional effect was favourable in most patients.