It was during the past few years that postprandial hyperlipidemia is believed to be more closely related to a risk for coronary artery disease. However, the high variability in the postprandial triglyceride (TG) levels could have made overlooked such diagnostic value in estimating an individual's risk for coronary artery disease. To minimize the impact of such variability, the remnant lipoproteins, TG-rich lipoproteins, might be measured in cholesterol using remnant-like particles (RLP-C) assay as a more reliable marker. In place of the previous cholesterol reagent (CHOD-Iodine) in RLP-C assay, the RLP-C assay was improved by employing a new cholesterol reagent (POD-EMSE). The correlation between these two assays was high (r = 0.978). The variations in RLP-C levels in healthy normolipidemic subjects was within 7.5mg/dl in a day. In oral-fat loading test, the variations of RLP-C levels in healthy subjects were also within 7.5mg/dl. However, patients with coronary artery disease showed much higher levels (over 7.5mg/dl) of RLP-C during the test. In conclusion the RLP-C assay can be used for the measurement of remnant lipoproteins in serum prepared from the fasting as well as postprandial states for predicting subjects who may be at risk of coronary artery disease.