In 1986, 1124 patients were selected for coronary artery bypass surgery (CABG). Of patients in line for CABG 25 (2.2%) died of a cardiac cause before operation. This complies with a cardiac mortality risk of 8.3 patients per 100 patient years follow-up. To assess patient characteristics predictive for early mortality before surgery, 25 deceased patients were analysed and compared with 50 controls matched by age, gender, type of surgery and priority. Using multivariate analysis, cardiac enlargement on chest X-ray, positive exercise testing with short duration (less than 6 minutes), smoking, coumarin treatment, unstable angina just prior to angiography and left main or three-vessel disease were independent predictors for death while waiting for CABG. We conclude that patients with the above mentioned characteristics have an increased short term mortality while waiting for CABG. These indicators may contribute important information for determination of priority in patients at high risk while waiting for CABG.