Endocardial cushion defect (ECD) can be partial (with two distinct valves) or complete (only one atrioventricular valve), and surgical therapy is usually required. The optimal surgical technique is controversial but De Vega's annuloplasty is widely performed. Tricuspid valve thrombosis are rarely seen after surgery. We present a 39-year-old male patient with tricuspid valve thrombosis after De Vega's annuloplasty without the use of a ring.