We studied the echocardiograms of 243 school children who needed further examination of the heart beyond electrocardiography, auscultation, chest X-ray and/or medical history. 1. Thirty of them showed mitral valve prolapse including two with Marfan's syndrome, one with arrythmias exaggerated by physical exercise and a case with left ventricular volume overloading. 2. Five of eight patients who were suspected to suffer from a atrial septal defect by electrocardiography and auscultation showed right ventricular volume overload echocardiographically. In four of the five, an intracardiac shunt at the atrial level was confirmed by contrast echocardiography. 3. One case with right ventricular hypertrophy as determined by electrocardiography showed right ventricular pressure stress echocardiographically. He was diagnosed as having primary pulmonary hypertension by cardiac catheterization. 4. A ventricular septal defect and patent ductus arteriosus were diagnosed in six cases by auscultation or phonocardiography, but not so by echocardiogaraphy. Echocardiography as a secondary examination is not only diagnostic in itself but also is beneficial in determining whether or not further examination (cardiac catheterization) is needed.