Late endocarditis after surgical repair of tetralogy of Fallot is rare. We describe a case of endocarditis following cholecystectomy in a 22-year old patient with repaired tetralogy of Fallot. After cholecystectomy, the patient was referred to a cardiology clinic with unexplained fever and suspicion of endocarditis. Echocardiography revealed a large mass at the basal level of interventricular septum. Endocarditis was diagnosed on the basis of clinical and echocardiographic findings and antibiotic treatment was initiated immediately. Nine days later, the clinical status of the patient deteriorated and urgent surgery was performed. Patch dehiscence which mimicked a large vegetation, and multiple vegetations on the patch were found during operation. The patch was removed and ventricular septum defect was repaired with a new dacron patch. Enterobacter agglomerans was isolated in the vegetation cultures.