Closure of ventricular septal defect (VSD) in children with elevated pulmonary vascular resistance (PVR) is associated with significant morbidity and mortality with pulmonary hypertensive (PH) episodes being a major postoperative problem. Flap valved closure of VSD is reported to decrease morbidity and mortality. We report our experience of closure of a VSDs in patients with severe PH, using a valved patch in an effort to reduce the risk of operation. Eighteen consecutive patients with a large VSD with severe PH (mean PVR>8 Wood units) underwent flap valved closure (as described by Novick et al.) of VSD during a one-year study period. The mean age at surgery was 8.3±3.9 years (range: 3-13 years). Mean PVRI was 13.02±4.05 Wood units. In-hospital 30-day mortality was 5.6% (1/18). Mechanical ventilation time averaged 11.6±8.1 hours. Postoperative pulmonary artery pressures were significantly reduced. Four patients had PH crisis postoperatively. Obvious opening and closing of the flap valve was detected by echocardiography in eight patients. There were no late deaths due to cardiac causes. Closure of a large VSD in patients with severe pulmonary hypertension could be performed with low morbidity and mortality when a flap valve patch was used.