Objective: Significant changes have occurred in the management of pediatric patients with ventricular septal defect such as early surgical repair of the defects. The objective of this study was to investigate the effects of early closure of isolated ventricular septal defects on pulmonary artery pressure. Materials and Methods: Forty-nine patients undergoing surgery due to ventricular septal defects between January 2001 and January 2004 were enrolled in the study. The patients were classified into two groups in terms of their age at the time of the operation. Those who had been operated on before the age of 2 formed Group 1 (n=24) and those who had been operated on after the age of 2 formed Group 2 (n=25). Preoperative and postoperative (at 1 year) echocardiographic measurements of pulmonary artery pressure values were recorded for all patients. Results: No statistically significant differences were found between groups 1 and 2 in terms of preoperative pulmonary artery pressure or pulmonary vascular resistance values. However, mean postoperative pulmonary artery pressure values were significantly lower in Group 1 (24.41 ± 0.63 mmHg) when compared with those in Group 2 (37.06 ± 1.53 mmHg) (p = 0.0001). No early or late mortality occurred in the groups during a mean follow-up period of 2 years. Conclusion: Our results suggest that surgery is more beneficial at an earlier age before the onset of pulmonary vascular disease. Surgery at an early age, if possible during infancy, may offer an opportunity to lead a nearly normal life for patients with VSD.