The clinical features of 10 children, in whom the diagnosis of a cardiac tumor has been made, are reviewed. There were nonspecific systolic murmurs in 9 patients, depression of the S-T segment in the ECG of 7 children, and premature extrasystoles or supraventricular tachycardia in 4 children. X-ray always showed mild to moderate enlargement of the heart, but an abnormal contour could be detected only in 2 of the patients. While findings of cardiac catheterization were unspecific, the diagnosis could be made angiographically in 8 cases. Invasive studies, however, are now only indicated, if a proper diagnosis cannot be made by means of echocardiography. The diagnosis should be suspected in children with a nonspecific murmur, cardiomegaly and ECG-changes. Usually the diagnosis of a cardiac tumor is an indication for operation.