Four patients with fungal endocarditis after open-heart surgery were confirmed microbiologically. Two of them died, and the other 2 were treated with intravenous administration of miconazole. Clinical symptoms of the disease were similar to those of bacterial endocarditis, but headache and sweating were more predominant. This complication was likely to be found and treated with effective anti-fungi drugs. We suggest that reoperation is the only possible way to cure those with residual shunt or vegetation, and that prevention of postoperative fungal endocarditis is of great importance because of its refractoriness. Measures of preventing fungal endocarditis after open-heart surgery are discussed.