The increasing concern about the high cost of health care led the authors to conduct a pilot study on the overall cost and cost variability for patients who underwent coronary artery bypass grafting. They reviewed the charts of 50 randomly selected patients to determine actual costs of catheterization and bypass grafting. Four patients had single-vessel disease, 12 double- and 34 triple-vessel disease and 13 had moderate to severe impairment of ventricular function. The length of hospital stay ranged from 8 to 43 days (mean 16.5 days). The duration of stay in the recovery room and intensive care unit ranged from 21 to 356 hours (mean 91.6 hours). Operative time ranged from 2 to 6.5 hours (mean 3.95 hours). Using several accepted cost-allocation methods, the authors developed a valid, complete breakdown of clinical and nonclinical costs. Total cost was directly related to the length of hospital stay, left ventricular function, secondary diagnosis and number of diseased vessels. Further studies will address clinical factors related to cost and cost effectiveness of coronary artery bypass grafting as opposed to other forms of treatment for coronary artery disease.