Considering that coronary artery disease (CAD) is the number one cause of death in the developed countries and higher than half of patients with severe clinical symptoms do not have any predictive sign for CAD necessitate the development of advanced screening tests. Coronary artery calcium score (CCS) test depending on the principle of measurement of calcium level in atherosclerotic lesions is one of the most important steps in this field. Coronary artery calcification is recognized as an active process that is closely linked to vascular inflammation and predicts future cardiac events. Presence of calcium in vascular lesions allows us to assess the lesion burden. Nowadays spiral CT is being widely used to define structural changes and calcium deposition in coronary artery segments instead of electron beam tomography which is initially used. However, since there are numerous non-calcified lipid-rich plaques with thin fibrous caps besides calcified plaques in CAD patients, CCS is not efficient test to evaluate the risk of CAD alone. The CCS percentiles defined for age and gender are more relevant in assessing risk and more predictive of hard cardiac events than absolute CCS. In asymptomatic cases, while being zero of CCS do not eliminate the risk of occurring acute cardiac events and the possibility of myocardial ischemia, the presence of high CCS rises predictive value of Framingham risk score (FRS) for coronary death and non-fatal myocardial infarction. Finally, the CCS is valuable test screening tool in selected patients such as those with an intermediate FRS, as recommended by the current guidelines; high coronary calcium score is closely related with the increased risk of CAD and serious cardiac events, and signs to requirement for secondary prevention and other advanced techniques in the diagnosis of CAD. (Anadolu Kardiyol Derg 2008; 8: 1; 12-4)