INTRODUCTION Accumulated evidence shows that erectile dysfunction (ED) may be a precursor of coronary artery disease (CAD). AIMS The purpose of this study was to explore the differences in coronary phenotypes between patients with ED and patients with angina pectoris. METHODS The study enrolled 30 ED patients (study group) and 120 age-matched angina patients who had no ED (control group). All patients had angiographically documented CAD. MAIN OUTCOME MEASURES The differences in demographic characteristics, biochemical profiles and coronary characteristics between the study and control groups were compared. RESULTS Diabetes mellitus (DM) and obesity defined by body mass index were more common in the study group than in the control group. The mean number of lesions and mean number of vessels with evidence of CAD were significantly different between the study and control groups (2.3 ± 0.1 vs. 2.2 ± 0.1, P < 0.001; 2.0 ± 0.2 vs. 1.8 ± 0.1, P < 0.001). The distribution of vessel involvement was similar between the groups, except for more common involvement of the ramus in the study group. There were no differences in distribution of lesion sites between the two groups. The control group had a higher percentage of type A stenotic lesions than the study group (16.3% vs. 2.9%, P = 0.004). Significant differences were also observed in type C lesions (52.9% in study group vs. 38.0% in control group, P = 0.026). Fewer calcified, irregular, and bifurcated lesions were present in the study group compared to control. CONCLUSIONS This study documented coronary phenotypes in ED patients without symptomatic CAD. Although the artery size hypothesis and ED had well been thought to be a precursor of CAD, the severity of coronary lesions in these patients was not more benign than that observed in angina pectoris patients who have no ED.