Background This study was performed to measure right and left ventricular volumes in Ebstein's anomaly before and after operation. Methods Twenty-six consecutive patients were operated on with tricuspid valve repair and plication of the atrialized right ventricle, associated with a bidirectional cavopulmonary shunt in 15 patients. Right ventricular (RV) and left ventricular end-diastolic and end-systolic volume indexes were measured by x-ray computerized tomography before and after surgical repair. Left ventricular stroke index and ejection fraction were calculated. Results Before surgery, the mean stroke index of the atrialized RV was 36 ± 33 mL/m 2 , with severe reduction in 9 patients and aneurysmal aspect in 2 patients. After surgery, the atrialized RV was no longer identifiable. Both RV end-diastolic volume index and stroke index of the remaining effective RV were reduced. Bidirectional cavopulmonary shunt was a determinant factor of decrease in the effective RV end-diastolic volume index after repair. Conversely, left ventricular ejection fraction and stroke index increased significantly after surgery. Conclusions The atrialized RV with dyskinesia seems a good indication for a plication. RV end-diastolic volume index of the effective RV decreased after surgery. In severe cases, bidirectional cavopulmonary shunt was useful by decreasing RV end-diastolic volume, thus preventing further RV dilation. In all cases left ventricular ejection fraction and stroke volume index increased after surgery.