Cor triatriatum dextrum is a rare congenital malformation, usually associated with complex right heart abnormalities, characterized by a membrane that divides the right atrium into two chambers. It is considered the result of the incomplete and abnormal regression of the embryonic right valve of the sinus venosus. With an incomplete regression, a fenestrated or an unfenestrated membrane may persist in the right atrium. Cor triatriatum dextrum may be seen with congenital cardiac defects associated with the right heart. We have diagnosed infective endocarditis in a 19 year old male patient with asymptomatic incomplete cor triatriatum dextrum, PFO and valvular-infundibular severe pulmonary stenosis based on the Duck criteria, with a positive blood culture and 3 minor criteria. Echocardiography did not reveal any vegetations. Antibiotherapy was given and then regions responsible of the stenosis were resected surgically. After surgery a small outlet type VSD development was observed. (C) 2007 Elsevier Ireland Ltd. All rights reserved.