Objective: We report our results of hybrid perventricular procedures to close muscular ventricular septal defects (MVSD) with Amplatzer Duct Occluder (ADO). Background: Apical MVSDs are limited to approach by traditional surgery or percutaneous closure especially in small infants. Hybrid perventricular procedure can be a good option to close apical MVSDs in the patients with other cardiac anomalies or previous pulmonary artery bands requiring surgical treatment in addition to small infants. Method: We reviewed the data of 5 patients who underwent hybrid perventricular MVSD closure using ADO between March 2006 and May 2011. Their median age was 11 months (25 days-25 months), and median body weight was 9.1 kg (5-15). All had apical MVSD with additional inlet or muscular trabecular VSD in 3 patients. The procedure was done under cardiopulmonary bypass in one patient and under beating heart in 4 patients with guidance by transesophageal echocardiography. Results: The mean defect size was 6.2 mm (4-7). The ADO was selected for the pulmonary side size to be at least 1-2 mm larger than the maximum or largest MVSD size, and the median ratio of ADO/defect size was 1.6 (1.4-2.5)/1. The procedure was successful in all patients. One patient showed pseudoaneurysm at left ventricle which regressed spontaneously a few months later. During median follow up of 2.4 years, residual VSD was minimal in 3 patients, no VSD in 2 patients. Conclusions: Hybrid perventricular closure of MVSD with ADO can be performed with a low risk. This procedure is encouraging even in small infants, especially in patients with other cardiac anomalies requiring surgical repair. Key words: 1. Hybrid approach 2. ventricular septal defect 3. Amplatzer Duct Occluder (ADO) 4. perventricular closure