Aim To investigate the features of coronary artery calcification (CAC) determined by electron beam computed tomography (EBCT) in patients with coronary artery ectasia. Methods In 27 patients who were diagnosed as coronary artery ectasia by coronary angiography, EBCTs were performed for calculating calcium score (CS). The calcium scores were compared between patients and angiographically normal subjects matched for sex and age. Results The CAC prevalence, CS median and LN (the mean natural logarithm transformation of calcium score) were all greater in ectasia group than in control group (p<0.01 or 0.001). Coronary artery calcification existed in 17 of the 21 patients with atherosclerotic coronary artery ectasia (81.0%). The mean LN was significantly lower in vessels with diffuse ectasia than in those with discrete ectasia (1.22±1.79 vs 2.86±1.85, p<0.05). Conclusion Coronary artery calcification exists in most of the patients with atherosclerotic coronary artery ectasia, and the extent of calcium is related to the types of ectasia.