Summary: Two patients presenting with simultaneous rightand left-sided infective endocarditis requiring surgical intervention are reported. One patient developed aortic and pulmonic valve endocarditis following dental extraction, while the second patient developed mitral and tricuspid valve endocarditis secondary to a large body burn. The bilateral semilunar valve endocarditis was treated by porcine aortic valve replacement and debridement of the pulmonic valve. The bilateral atrioventricular valve endocarditis was treated by mitral and tricuspid valve replacement with porcine valves. The frequency and clinical settings in which this condition is likely to present are discussed.