PURPOSE: We evaluated the CT characteristics of atherosclerotic coronary plaques in relation to the degree of stenosis. MATERIALS AND METHODS: We analyzed coronary CT angiography of 239 patients showing plaques obtained from December 2005 to May 2008, in terms of degree of stenosis (mild <75% area stenosis; severe >75%), location of plaque, plaque types, and calcium score. RESULTS: Total 694 segments were found to have plaque in 239 patients. Multiple lesions were found in 151 patients (57.1% of patients with mild stenosis; 87.5% with severe stenosis). The type of plaque was classified into noncalcified, mixed, and calcified in 26.7%, 22.5%, 50.8% of patients with mild stenosis and 22.9%, 56.3%, 20.8% with severe stenosis, respectively. The most common plaque location was the proximal left anterior descending artery. In patients with calcified or mixed plaques, there was a significant correlation between degree of stenosis and calcium score. CONCLUSION: Mixed plaque was the most common type in severe stenosis, while calcified plaque was the most common in mild stenosis. Multiple lesions were found in most patients with severe stenosis. The calcium score was significantly higher in patients with severe stenosis.