The purpose of this study was to evaluate the LDL-C/apoB ratio as a marker of LDL-particle size in CAD patients with DM in a hospital-based cross-sectional study, and to clarify the relationships between the LDL-C/apoB ratio and TRL-related markers (TG, VLDL, RLP-C,apo C-II, and apo C-III), which are indicators of TG metabolism. The gene discussed is APOB; the disease is coronary artery disorder.