To determine predictors of early death after coronary angiography in patients with significant left main coronary artery disease (greater than or equal to 60% diameter narrowing, LMCAD), we reviewed the clinical records of patients with LMCAD who died after angiography. Of 1,288 patients with LMCAD studied between January 1978 and October 1989, 21 died within 2 days after angiography (group 1). As a control group, 85 patients were randomly sampled from 1,196 patients who survived at least 30 days after angiography (group 2). The predictors of early death after angiography in patients with LMCAD were older age (P less than 0.05), New York Heart Association Class III or IV (P less than 0.005), shorter duration of unstable angina (P less than 0.005), higher left ventricular end-diastolic pressure (P less than 0.006), lower ejection fraction (P less than 0.005), and significant left circumflex artery disease (P less than 0.006). The use of heparin infusion after angiography did not appear to be a significant factor. It is suggested that earlier operation or more aggressive management be undertaken in patients who, at cardiac catheterization, have significant LMCAD associated with the above-listed variables.