During the years 1959 to 1974, 99 patients with patent ductus arteriosus were admitted to National University Hospital. These includes 5 patients with additional cardiovascular and 5 patients with severe pulmonary hypertension. All were operated upon except three refused operation. In all instances, the diagnosis was made by history and physical, roentgenological and electrographic examinations. In addition, in 53 patients, special diagnostic procedures were carried out either for diagnosis or for evaluation of pulmonary hypertension and associated cardiovascular anomalies. Right cardiac catheterization was resorted to in 51 patients. In one of these patients catheterization was incorrectly interpreted [ventricular septal defect]. Retrograde aortogram was performed in two patients. In both cases the ductus itself was visualized on the x-ray film. An additional vascular anomaly, namely the persistent left superior vena cava, was confirmed by retrograde angiogram in one of them. In 5 cases the pulmonary arterial pressure was elevated well over 80 mmHg. In these instances,the operative mortality was 80% [4 out of 5 patients]. The management of patent ductus arteriosus when associated with severe pulmonary hypertension. and/or other cardiac anomalies is controversial. Opinions differ as to how to close the ductus and to repair the cardiac anomalies as well as to whether a one-staged or two-staged procedure should be resorted to. The author is of the that each case must be evaluated individually before any specific surgical treatment is ou.tlined. The literature on the subject is reviewed in this paper.[KTCS 1974;1:85-92]