Double-chambered right ventricle (DCRV) is a rare congenital heart disease in which muscular bundles growing in the subinfundibular area are hypertrophied, separating the right ventricle (RV) into two chambers. The muscular bundles tend to cause right ventricular outflow tract obstruction (RVOTO). It is an entity not to be confused with the spectrum of diseases with pulmonary stenosis, such as Tetrology of Fallot, in which the infundibulum rather than the subinfundibulum is stenotic. Almost 90% of DCRV cases have associated membranous ventricular septal defects (VSD). Some believed the hypertrophied muscular bundles in DCRV are induced by VSD, in order to prevent the pulmonary circulation from overloading. A right intraventricular pressure gradient of at least 20 mmHg should be measured during transthoracic echocardiography for DCRV to be considered. When treated properly with surgery, usually myectomy of the hypertrophied muscular bundles, the prognosis is optimal with complications occurring rarely. However, the subinfundibulum is not always well visualized in standard planes of transthoracic echocardiography, and measuring the RV pressure gradient is not a routine. While most prospective ECG-gated cardiac computed tomography (CT) images disclose heart appearances during the diastolic phases, hypertrophied muscular bundles in DCRV are often reasonably more visible when the heart is contracted in systole. Observation during surgery is also not always straightforward because operated hearts are usually in a state of induced diastolic arrest during cardiopulmonary bypass. All of which may lead to overlooking of underlying DCRV and thus reoperations when RVOTO gets worse. Correct diagnosis before surgery is thereby crucial. Numerous studies have already explored the diagnostic value of conventional echocardiography in DCRV. Data regarding its diagnosis via ECG-gated cardiac CT on the other hand is relatively scarce, while CT still remains a popular modality of choice in Asia. We not only share our experience in diagnosing DCRV with cardiac CT in this study, to our knowledge this is also the first of its kind to gather such a considerable amount of cases and perform quantified measurements.