In this article, we describe a multifactorial cardiac risk index that can be used to assess patients undergoing noncardiac surgery. The index is a modified version of an index that was previously generated by Goldman and coworkers on a set of 1001 consecutive patients and prospectively validated in our clinical setting (a general medical consultation service in a large teaching hospital) on 455 patients. We present a Bayesian approach to assessing cardiac risks by converting average risks for patients undergoing particular surgical procedures (pretest probabilities) to average risks for patients with each index score (posttest probabilities). A simple nomogram is presented for performing such a calculation.