Background: The relationship between lipid profile and coronary plaque tissue characteristics in patients with stable angina pectoris (SAP) are unclear. The aim of this study was to evaluate the relationship between the tissue characteristics and lipid profile,and predictors of unstable plaque in patients with SAP by virtual histology intravascular ultrasonography (VH-IVUS). Methods: VH-IVUS was performed in patients with SAP (61.7짹9.2 years, 174 males, n=266) at the time of coronary angiography. Unstable plaques are characterised by thin-cap fibroatheroma (TCFA) or ruptured plaque or remained thrombus on VH-IVUS. Results: The present study showed that unstable plaque was 34 (61.6짹9.2 years, 24 males, 12.8%) in patients with SAP. The percent plaque area of minimum luminal area in high low-density lipoproteincholesterol / high-density lipoproteincholesterol (LDL-C/HDL-C) ratio patients was significantly higher than in the low LDL-C/HDL-C ratio patients (72.7짹9.5% vs.69.9짹9.3%, p=0.035).LDL-C/HDL-C ratio>2.0 was an independent predictor for unstable plaque in patients with SAP (odds ratio 5.252, 95% confidence interval 1.132–24.372, P=0.034). Conclusion: Elevated LDL-C/HDL-C ratio is a positive predictor for coronary plaque vulnerability in patients with SAP.