Background: Children with ventricular septal defects (VSD) can have chronic volume overload, which can result in changes of left heart echocardiographic parameters. Objectives: To evaluate the changes before and after surgical closure, we divided the children into 3 groups according to the degree of mitral regurgitation (MR) and reviewed their echocardiographic characteristics at serial follow up after surgical closure. Method: We retrospectively reviewed the echocardiographic data of 40 children who underwent surgical closure of VSD at preoperatively and at 1, 3, and 12 months postoperatively. We observed left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic dimension (LVEDD), and left ventricular end systolic dimension (LVESD), mitral valvular characteristics, including degree of MR and mitral valve annulus, and left atrial (LA) characteristics including volume. Results: Preoperative LVEDV, LVEDD, LVESD, mitral valvular annulus, LA volume, and LA dimensions were significantly larger in children with MR. In addition, there were significant decreases in LVEDV, LVEDD, LA volume, and LA dimensions at 1, 3, and 12 months postoperatively. The degree of MR also improved to a lower grade after surgical closure of the VSD without additional mitral valve repair. Conclusion: The echocardiographic parameters of left heart dilation and MR in children with VSD had improved within the first year after surgical closure without additional mitral valve repair. Furthermore, in all of the patients with VSD, regardless of MR, LA dilation was reduced within 3 months after surgical closure of the VSD; however, LV and mitral valve annular dilatation decreased within 12 months.