In the course of treating approximately 740 patients with open heart surgery, we experienced 38 patients who underwent open heart surgery as the second operation after initial operation on heart at Seoul National University Hospital. Twenty four cases of congenital 14 acquired heart disease were found. There was 14 operative death of 38 patients, resulting in overall mortality 36.8 %; 8 death [33.3 %] in congenital group, 6 [42.9 %] in acquired group. Principal causes of death were lower cardiac output syndrome and congestive heart failure. Compared with foreign report, as this data shows still high overall mortality, this review suggests that second open heart surgery can be performed safely with reasonable operative mortality and satisfactory prognostic outlook in the near future.[KTCS 1979;3:263-268]