Between January 1980 and December 1983 the medical and social status of 423 patients who were considered candidates for aortocoronary bypass surgery (ACBS) was assessed by a questionnaire, at a mean of 16 months after coronary angiography. Of these patients 54 had refused surgery, 15 were re-operated, 23 had angioplasty and seven had died on the waiting list. After exclusion of these 117 patients, 306 remained, who form the basis of this report. Fifty three patients (17%) had retired before surgery, four (1.3%) had died perioperatively and 19 were on sick-leave for less than three months. Of those who were still employed pre-operatively, 102 (44.3%) went back to work, 85 (37%) had retired and 42 (18%) were on sick-leave for longer than three months. Significant differences were noted between the 102 working and the 85 retired patients as far as medical and social factors are concerned. Of the medical factors, post-operative freedom of symptoms (P less than 0.0001), postoperative exercise tolerance (P less than 0.0001) and completeness of revascularization (P less than 0.05) seemed to have influence on return to work. Of the social factors, age (P less than 0.0001), type of occupation (P less than 0.0002), duration of preoperative absence from work (P less than 0.001) and heavy manual work (P less than 0.05) showed significant differences between the groups. Since duration of preoperative absence from work is the only preoperative factor that can be modified, strategies for improving the return-to-work rate should aim at the shortening of waiting times for coronary angiography and ACBS.