BACKGROUND The role of triglycerides as a risk factor for coronary artery disease (CAD) is controversial. In prospective studies, which have reported discrepant results, triglycerides have generally been measured with subjects in the fasting state. Taking into account the fact that the average person spends up to 18 h per day in the post-prandial state, fasting triglyceride levels alone are inadequate to describe the actual effective concentrations, metabolism and atherogenicity of triglyceride-rich lipoproteins. Therefore, investigations of the dynamic post-prandial triglyceride metabolism of patients with CAD in comparison with healthy controls are necessary. METHODS We studied the post-prandial metabolism of lipids in 99 men: 50 male patients with CAD confirmed by angiography and 49 matched healthy men. After an overnight fast of 12 h, the subjects (aged 40-60 years) ate a standardized oral fat load (3.2 MJ; 49 g fat = 58% of the total energy content). Blood samples for lipid analyses were drawn immediately prior to and hourly during the 6 h period after ingestion of the meal. RESULTS As required by the study design, fasting triglyceride and total cholesterol levels did not differ between patients and controls; however, high-density lipoprotein (HDL), HDL2 and HDL3 cholesterol levels were significantly lower in the CAD patients. The highest post-prandial triglyceride serum concentrations were observed 3 h after ingestion of the oral fat load both in cases and in controls. Generally, CAD patients had slightly higher triglyceride values than did controls and, at the 5 h measurement point, this difference was significant. CONCLUSIONS The results suggest that there are differences in triglyceride metabolism between patients with CAD and healthy controls after a challenge with a moderate amount of fat. These differences can best be observed in the degradation phase of post-prandial lipaemia.