Abstract Seventeen cases of Ebstein's anomaly have been presented; the diagnosis was confirmed by autopsy in 6, and made on clinical grounds in the other 11. The series includes the youngest patient dying of the lesion, a stillborn infant, and the fifth oldest patient thus far reported (64 years). The features associated with this condition are presented as found in this series and compared with those observed by previous authors. It is emphasized that the history and physical and laboratory examinations are sufficiently characteristic to allow the diagnosis to be made with a high degree of accuracy in the majority of cases. As with any condition, the entity is represented by a spectrum in every regard; and as to the cases on either end of the spectrum, one must combine a high degree of suspicion with a knowledge of the spectrum, else the true diagnosis will only be made at the autopsy table or at the time of ill-advised operative procedures. Particular emphasis is given to the group of patients over 50 years of age who represent about 5 per cent of the patients with Ebstein's anomaly. They may be, and in fact generally are, unusual in all respects when compared to the “typical” case. Comments are made on the natural history of the young patient, and it is urged that extensive diagnostic or surgical procedures be delayed until signs of deterioration appear, since tolerance of such procedures may be poor. The etiology of the anomaly remains obscure, and a practical and satisfactory therapeutic approach remains for the future.