Apolipoprotein E (apo E) is a constituent molecule of the triglyceride-rich lipoproteins and participates in their clearance. Polymorphisms in the apo E gene are associated with increased fasting and postprandial levels of triglycerides. We studied 66 patients with the metabolic syndrome, none of whom had diabetes. Details were recorded for cholesterol, triglycerides, apo AI, apo B, insulin, homeostasis model assessment of insulin resistance, homeostasis model assessment of insulin secretion, uric acid, 24-h uric acid urinary excretion, high-density lipoprotein cholesterol, waist to hip ratio, body mass index, and age. The patients were given a 60-g fat overload (Supracal), and measurements were made at 4 h of cholesterol, triglycerides, high-density lipoprotein cholesterol, apo AI, and apo B. Patients who did not have the E3/3 genotype had an odds ratio of postprandial hypertriglyceridemia of 6.2 (confidence interval, 1.41-16.08; P = 0.01) and an odds ratio of hyperuricemia compared with the E3/3-positive patients of 7.5 (confidence interval, 1.04-39.31; P = 0.02). This study shows that patients with the metabolic syndrome who do not have the E3/3 genotype have a greater risk of hyperuricemia and postprandial hypertriglyceridemia after a fat overload.