Clinical significance of preoperative physical training was studied in 29 patients with cardiovascular diseases who were to undergo elective abdominal surgery. The exercise testing on admission revealed that 11 of the 29 were in inadequate physical condition. These 11 underwent a preoperative physical training program which proved to be effective in 7. The incidence of postoperative complications was significantly higher in the 4 patients with inadequate physical fitness than in the 25 patients who were fit. Two cardiac deaths occurred postoperatively in the former group, while no cardiac complication or death was found in the latter group. These results indicate that preoperative physical training is a useful adjunct to regular methods for estimating cardiac risk and also to reduce the risk.