From March 1993 to February 1993, 36 patients with chronic renal failure underwent cardiac surgery with intraoperative hemodialysis (HD). We examined and compared the medium term results of those patients cased upon the time periods of operation and types of heart disease. With respect to the time periods of operation, the 1st term (n = 12) was between March 1985 and February 1989, and the 2nd term (n = 24) was between March 1989 and February 1993. Concerning types of disease, Group A was comprised of 24 patients with ischemic heart disease, and Group B was comprised of 12 patients with valvular or congenital heart disease. Only one early death was observed in the 1st term (8.3%: LOS). As for late death, 5 cases were observed in the 1st term (45.3%), and 2 cases were observed in the 2nd term (8.3%). The actuarial survival rate (post 3 years) was 72.7% in the 1st term and 91.3% in the 2nd term. In each case, the survival rate of the 2nd term was significantly better than the that of the 1st term (p < 0.025). When compared cased upon the types of disease, the actuarial survival rate (post 6 years) was 84.6% in Group A, and 45.5% in Group B, respectively. This difference was statistically significant (p < 0.05). Causes of late death were cerebral hemorrhage in 5 cases, sudden and unknown in one and DIC in the remaining one patient. There were many postoperative complications in this series in addition to the above stated fatal ones. The majority of them, however, were successfully treated, if early diagnosis of them was obtained. During the perioperative period through the long-term period, incidents of fatal hemorrhage among patients on chronic dialysis were reduced by 1) strict management of hypertension; 2) HD without use of Heparin; and 3) with respect to patients who required Warfarin after valve replacement, through the careful anti-coagulant therapy which maintained the thrombo-test (TT) value at precise levels.