The aim of this study was to quantitatively assess non-calcified coronary artery plaques and to determine their predictive value for the detection of coronary artery disease (CAD). A total of 179 patients underwent a calcium screening examination and a contrast-enhanced multidetector-row computed tomography angiography (MDCT) of the coronary arteries for various indications. The traditional calcium scores were evaluated and all examinations were reviewed for the presence of non-calcified plaques with an attenuation of 0–130 Hounsfield units (HU). The number, mean attenuation, and volume of these non-calcified plaques were recorded. All patients also underwent conventional catheter angiography. Coronary calcium was detected in 73% (131 of 179) of the patients. Overall incidence of purely non-calcified plaques was 30% (53 of 179). In 27% of the patients (48 of 179) no calcium was detected; however, 15% of these patients without calcifications showed non-calcified plaques (7 of 48). Significant correlations were found between the volume of calcified plaques, volume of non-calcified plaques, and total plaque volume. There were significant differences in plaque composition comparing different risk factor profiles and different stages of CAD. Volumetric assessment of non-calcified coronary artery plaques is feasible using contrast-enhanced MDCT. Screening for non-calcified plaques identifies patients with signs of CAD that are missed in a calcium screening examination.