Complications such as hypertension, non insulin-dependent diabetes mellitus (NIDDM) and cardiovascular diseases are more prevalent in obese patients than in normal weight individuals. However, considerable metabolic heterogeneity is found among obese patients. Studies published over the last 15 years have emphasized the role of body Fat distribution, especially of visceral adipose tissue accumulation as a critical correlate of metabolic abnormalities that have been in the past associated with excess fatness per se. Thus, excess visceral adipose tissue accumulation, which can be assessed by imaging techniques such as computed tomography, has been associated with hyperinsulinemia, insulin resistance, glucose intolerance which may lead to NIDDM among genetically susceptible individuals, hypertriglyceridemia, elevated LDL particle concentration, increased proportion of small-dense LDL particles and reduced plasma HDL cholesterol concentrations. Recent findings of the prospective Quebec Cardiovascular Study have emphasized that this cluster of metabolic abnormalities is associated with a substantial increase in the risk of ischemic heart disease (IHD). As most visceral obese patients have rather 'normal' cholesterol levels, it is suggested that IHD risk in these individuals should be assessed, in addition to conventional risk variables, by a triad of metabolic abnormalities which include hyperinsulinemia, hyperapo B and small-dense LDL particles. These atherogenic metabolic complications are even found in the pre-diabetic state, suggesting that the time for the development of 'preventive endocrinology' approaches may have come. It is proposed that simple and inexpensive variables such as the waist circumference and fasting triglyceride levels may be helpful markers for the screening of high risk patients who are carriers of the 'atherogenic metabolic triad' of visceral obesity.