This investigation was performed to study the reasons for receiving disability pension after aortocoronary bypass surgery. During the period March 1983 to November 1985, 250 patients underwent aortocoronary bypass surgery. At a mean follow-up of 4.9 years (range 3.6-6.7) after the operation, 31 patients were dead. Of the 219 survivors, all except four underwent a follow-up examination including an exercise test. The mean physical work capacity had increased from 92.2 W preoperatively to 119.3 W at follow-up (p < 0.001). At follow-up, however, 72 patients had received disability pension. The percentage of positive ECG-tests were equal among those who were working and those who had received disability pension. We suggest that, among those who had received disability pension, about 50% were in sufficient physical condition to manage their previous jobs or another type of job. Reasons other than physical working capacity played an important part as criteria for receiving disability pension.