To determine the long-term course of patients with normal coronary arteriograms, follow-up data regarding frequency of morbid cardiac events and extent of persistent clinical disability were obtained in 121 patients (72 women, 49 men; mean age 49 years) with normal (90%) or nearly normal (10%) coronary arteriograms. Mean length of follow-up was 4.3 years (range 1 to 11 years). Three (2.5%) patients died suddenly and unexpectedly. Four (3.4%) surviving patients suffered documented acute myocardial infarction (AMI) subsequent to initial arteriography. Three of seven patients who underwent repeat coronary arteriography were found to have disease in excess of that observed on initial arteriograms. The overwhelming majority (94% or 80%) of surviving patients continued to experience chest discomfort similar to that for which they underwent coronary arteriography and 75 (64%) continued to use antianginal drugs. Thus the finding of normal or nearly normal coronary arteriograms implies a highly favorable prognosis, although it does not establish immunity from a morbid cardiac event (AMI and/or sudden death); the likely basis for these events is progression of fixed obstructive disease, rather than coronary artery spasm or underestimation of extent of coronary disease by arteriography.