The prim ary objective in cardiovascular primary prevention is the avoidance of a first myocardial infarction and/or a first stroke. Current guidelines for prevention of cardiovascular diseases recommend administration of acetylsalicylic acid (ASA) and a statin when risk>20%/10 years (recommendation I A). The coronary calcium score has a strong predictive power which is independent of conventional risk factors and thus offers the most relevant information in addition to Framingham, PROCAM or ESC scores regarding coronary risk. For patients initially showing "intermediate" coronary risk (10-20%), guidelines suggest the determination of the coronary calcium score, which leads to better risk assessment and to identification of patients needing more aggressive lipid lowering (recommendation IIb B). Thus, the cardiac CT, on the one hand, aims the intense risk reduction needed in primary prevention to the high-risk patients, on the other hand, it avoids "superfluous" cardiac catheterizations, unnecessary statin therapies and potentially harmful ASA administrations. However, the proof of coronary calcium must not be confused with the presence of coronary artery stenoses: a positive calcium score in an asymptomatic person does not by itself indicate the need for a cardiac catheterization.