Background— Patients with extensive coronary artery disease (CAD) have better prognosis when treated with coronary artery bypass grafting surgery (CABG), especially when left ventricular dysfunction (LVD) is present. However, there are scanty data about the clinical course of patients not referred to CABG because of extensive and severe atherosclerotic involvement of distal coronary arteries (ENDCAD). The aim of this study was to evaluate patients with multivessel (MV) or left main CAD (LM) who had CABG precluded because of ENDCAD. Methods and Results— Between August 1999 and July 2001, 51 patients who had clinical indication but were not eligible for CABG because of ENDCAD were followed for at least 12 months or until death. There were 32 men and 19 women (age 61±9 years). Previous acute myocardial infarction (AMI) was present in 31 (60.8%), diabetes mellitus (DM) in 28 (54.9%), systemic arterial hypertension in 37 (72.5%), LVD (left ventricular ejection fraction <40%) in 26 (51%), 3 vessel CAD in 31 (60.8%), and LM in 4 (7.8%). During follow-up there were 20 cardiac (39.2%) deaths, 19 (37.2%) AMI, and 3 (5.8%) patients developed congestive heart failure. There were 2 (3.9%) noncardiac deaths. Patients with DM (60.7% versus 13%; P =0.001; odds ratio [OR], 10.30; 95% confidence interval [CI], 2.46 to 43.09), LVD (76.9% versus 0%; P <0.0001; OR, 4.33; 95% CI, 2.14 to 8.74), 3-vessel CAD (51.6% versus 20%; P =0.039; OR, 4.26; 95% CI, 1.16 to 15.69), and LM (100% versus 34%; P =0.019; OR, 1.25; 95% CI, 1.004 to 1.556) were more likely to die. There was no deaths in patients with 2-vessel CAD but they had more nonfatal AMI (43.8% versus 14.3%; OR, 4.667; 95% CI, 1.188 to 18.332). Conclusions— Patients in whom CABG could not be performed because of ENDCAD had high mortality, especially in the presence of LVD. DM (particularly insulin-dependent), LM CAD, and 3-vessel CAD were independent markers of increased risk.