Saline contrast echocardiography was performed in 889 children from June 1976 through February 1988. One-third of these studies were in postoperative patients. A patent foramen ovale was identified by finding right to left shunting on venous contrast injection in 37% of 127 children studied with a structurally normal heart. The incidence of such shunting was greater at younger ages (55% younger than 1 month versus 22% older than 1 month). In most patients with an atrial or ventricular septal defect, some right to left shunting was demonstrable. The technique was useful in distinguishing different forms of atrial septal defect and identifying muscular ventricular septal defects that were difficult to image directly. The technique was used in the catheterization laboratory to aid in the identification of congenital coronary artery fistulas and was diagnostic in two cases of pulmonary arteriovenous malformation. In patients with situs abnormalities, the technique was useful in identifying the systemic venous connections to the atria. Contrast echocardiography was also used in postoperative evaluations. The technique was useful in identifying patch leaks and residual defects after Senning, Mustard and Fontan operations, and after closure of atrial and ventricular septal defects. Most patients were found to have no superior vena cava obstruction by contrast echocardiography after the Senning or Mustard procedure. Contrast echocardiography continues to be a useful technique in the diagnosis of a wide spectrum of congenital heart disease, as well as in the postoperative evaluation of congenital heart surgery.