The concentration of low-density lipoprotein cholesterol has long been generally accepted as one of the strongest, independent risk factors for the development of cardiovascular disease. However, an increasing number of studies suggest that the ratio of apolipoprotein B (apoB) to apolipoprotein A-I (apoA-I) is a better risk predictor. In the present review, we focus on apoB and apoA-I as factors in predicting vascular risk in epidemiological studies only, and not in studies involving pharmaceutical intervention. The majority of studies in the present review show that apoB and the apoB/apoA-I ratio are independently and more strongly associated with vascular risk across varying age-groups and geographic regions than are conventional lipids, lipoproteins and lipid ratios.