Objective: To determine the diagnostic value of preoperative cardiac ultrasound in patients with Ebstein's anomaly in comparison with results found in operation and to evaluate the changes on cardiac ultrasound after surgery at the Hanoi Heart Hospital. Subject and method: Fifty two patients with Ebstein's anomaly received Carpentier's method from 01/2009 to 05/2014. Describing the lesions during operation. Preoperative and postoperative cardiac ultrasound by the standard angle recommended by the Association of American Ultrasound. Result and conclusion: All of the patients had heavy tricuspid insufficiency (TI) (3/4) or extreme heavy TI (4/4), the mean ofTl on ultrasound and surgery was 3.6 +/- 0.55. The results of ultrasound showed Ebstein type C was majority (32.7 percent), type D (26.9 percent), type B (25 percent), and type A (15 percent). Ultrasound had the right diagnosis compared to surgery for Ebstein type A, type B, type C, and type D was 75 percent, 84.6 percent, 92.1 percent, and 92.9 percent, respectfully. The lesions combined with Ebstein's anomaly in 50 percent. Among those, PFO accounted for 34.6 percent. When compared to surgery, the ultrasound had a right assessment in 75 percent of cases without combining lesions, right assessment of VSD, ASD, PFO, and PVS were 100 percent, although ultrasound still missed PFO (13.4 percent). TI was improved: the patients became mild TI (1/4) accounted for 69.2 percent. Heavy TI (3/4) became mild TI (1/4) and medium TI (2/4) in 85.7 percent, 14.3 percent. Extreme heavy TI (4/4) became mild TI (1/4) and medium TI (2/4) in 58.1 percent, 38.7 percent, one case had heavy TI 3/4 (3.4 percent). The area of the atrium was narrowed, function of right ventricular was improved.