From a study of four cases of postoperative fungal endocarditis and a review of the literature, the following points were determined: Cultures of the blood have been negative in 50% of cases. Blood cultures may be negative in spite of the fact that emboli occur and the organisms are capable of growing in simple media. In the absence of fungemia, the diagnosis has been made in some cases by section and culture of large emboli. Fungemia may be intermittent. Therapy with amphotericin B has been unsuccessful in 93% of cases. A few patients have recovered after reoperation, but further work is needed to demonstrate the value of surgical therapy.