Imaging for atherosclerotic disease as a modality of risk assessment to guide clinical intervention for primary prevention is becoming more widely acceptable. The greatest information about risk can be obtained by combining measures of atherosclerotic plaque burden with risk factors. Both contain useful and independent information. An unresolved issue is how best to combine risk factors and atherosclerosis imaging to yield a quantitative estimate of risk. Several alternative approaches are outlined in this article. If atherosclerosis imaging is to be used as an element in risk assessment, it must be done by physicians who are well versed in the concepts of global risk assessment and who are able to adjust preventive testing and therapies in ways to be cost-effective.