We investigated the diagnostic value of the chest radiograph and ECG in the evaluation of whether asymptomatic children with a cardiac murmur had a heart disease as defined by echocardiography. One hundred children aged 1 month to 15 years (median 30.1 months) were included. After physical examination, a tentative diagnosis was made: 53 children had no heart disease, 24 had a probable heart disease and 23 children were thought to have heart disease on the basis of clinical assessment alone. After information from chest radiography and electrocardiography was obtained, the diagnoses were re-evaluated. This resulted in a change of the tentative diagnosis in three children. However, the diagnosis in relation to the definite diagnosis by colour Doppler echocardiography was not changed to the correct diagnosis in any of these cases. In 24 cases, radiography suggested the presence of heart disease; however, only 10 of these had heart abnormalities on the colour Doppler echocardiogram (CDE). Three children had an abnormal ECG; all of these had abnormalities on the CDE, but they were already diagnosed as having heart disease by physical examination. We conclude that chest radiography and electrocardiography is of no help in the discrimination between heart disease and no heart disease in asymptomatic children referred for a cardiac murmur.