Between April 1984 and December 1992, 8 patients with concomitant malignant tumor were treated surgically for cardiac disease. The mean age was 58 years (range: 51 to 69), and there were 6 males and 2 females. There were 2 cases of ischemic heart disease, 3 cases of valvular heart disease, and 1 case of atrial septal defect (ASD). Gastric cancer was present in 4 cases, malignant tumor of hepatobiliary tract in 2, rectal cancer in 1, and lung cancer in 1. All patients were operated on in a two-stage fashion. In 6 cases, cardiac surgery including coronary artery bypass grafting (4 patients) and valve replacement (2 patients) were performed with an average of 58 days prior to the tumor resection. The other 2 patients underwent radical operation for a gastric or rectal cancer, followed by cardiac surgery for ASD or mitral stenosis about 2 months later. One patient died of respiratory failure 56 days after lobectomy following coronary artery bypass. There was one late death of local recurrence of rectal cancer 2 years after the operation. In conclusion, good surgical result can be expected with sequential operations for cardiac disease and malignant tumor, if curative resection of the tumor is possible.