Background: With improved survival following renal transplantation, the number of patients undergoing cardiac surgery has increased. The purpose of this study was to review the morbidity, mortality, and allograft function in renal transplant patients undergoing major cardiac surgery. Methods: Retrospective database review of consecutive renal transplant patients undergoing cardiac surgery from 1987 to 2002. Patients requiring dialysis (D) before cardiac surgery versus those with stable renal transplants (ND) were compared. Results: Cardiac surgery was performed in 46 patients during the study period. Twenty patients (42%) required dialysis (D) before surgery while 26 (58%) had stable allograft function (ND). Among patients who had stable allograft function prior to surgery, there was no allograft loss. In the ND group, preoperative and discharge creatinine levels were 2.17 ± 1.0 and 2.4 ± 1.5 mg/dL, respectively. All operative deaths occurred in the dialysis dependent group. The 30-day and 3-year survival, respectively was 80% and 20% in the D group compared to 100% and 69% amongst the ND group (p ≤ 0.01). Infectious complications consisted of pneumonia and sepsis each in 8.5% and of deep sternal wound infection in 4.3% of the entire group. Conclusions: (1) Morbidity and mortality of cardiac surgery in renal transplant patients with stable allograft function is low and stable allograft function can be maintained without allograft loss. (2) Mortality following cardiac surgery is significantly higher among renal transplant patients who become dialysis dependent and intermediate-term survival is poor.