The first reported case of Paecilomyces varioti endocarditis occurring on a porcine heterograft prosthesis is presented and the clinical and pathological features described in the four previously reported cases of prosthetic valvular endocarditis caused by this organism are reviewed. In each case, infection became apparent more than two months after cardiac surgery. Three of the four patients with infected aortic prosthesis developed outflow obstruction secondary to valvular vegetations. All patients died regardless of medical or surgical intervention. Appropriate therapy remains unknown.