Thirty five cases of Ebstein's anomaly were diagnosed by cardiac catheter study or echocardiography between 1962 and 1984. The anomaly was an isolated abnormality in 27 patients; the remainder had additional heart lesions. Six patients have died and four of these had other cardiac lesions. Thirteen are currently symptom free. Twelve cases presented with cyanosis and heart murmur on the first day of life. Eight of these had associated thrill which is a rare finding in neonates. As pulmonary vascular resistance fell there was clinical improvement. This was assisted by oxygen treatment. Another two cases presented in the first week of life and 10 in the first decade with a murmur or supraventricular tachycardia. Eleven cases presented as adolescents or adults with a murmur, cardiomegaly, or cardiac symptoms. Three patients were seen initially in the sixth decade. Clinical diagnosis was correct in only one adult. Twenty five patients had cardiac catheterisation. Important arrhythmias occurred in 10 cases, and two required cardioversion. Difficulty was experienced in entering the pulmonary artery in 11 infants and children. Diagnosis at initial catheter study was incorrect in four patients. Echocardiograms were recorded in 29 cases. Earlier M mode measurements of time delay of tricuspid closure compared with mitral closure did not always lead to the correct diagnosis. Cross sectional studies gave good images of tricuspid leaflet displacement, its tethering, and the atrialised portion of the right ventricle and have facilitated the diagnosis of more cases in recent years. Echocardiography is the procedure of choice for diagnosis of Ebstein's anomaly.