The present study evaluated the application of three dimensional echocardigraphy (3DE) in the diagnosis of atrial septal defect (ASD) and the measurement of its size by 3DE and compared the size with surgical findings.Two-dimensional and real-time three dimensional echocardiography (RT3DE) was performed in 26 patients with atrial septal defect,and the echocardiographic data were compared with the surgical findings.Significant correlation was found between defect diameter by RT3DE and that measured during surgery (r=0.77,P