Backgrounds: Dyslipidemia is an important cardiovascular risk factor. We evaluated the relation between dyslipidemia and plaque composition in patients with coronary artery disease. Methods: Study subjects consisted of 114 dyslipidemic patients (mean 59.7 yrs old, 75 males) and 209 normolipidemic patients (mean 62.6 yrs old, 151 males), who underwent virtual histology-intravascular ultrasound (VH-IVUS) examination. Each volumetric data was adjusted for the different lesion length via dividing by lesion length. Results: Dyslipidemic patients were younger (p=0.036), had higher total cholesterol (226짹64mg/dL vs. 168짹30mg/dL, p<0.001), triglyceride (202짹185mg/dL vs. 145짹77mg/dL, p<0.001), high-density lipoprotein cholesterol (46.5짹11.0mg/dL vs. 42.5짹10.5mg/dL, p=0.002), and low-density lipoprotein cholesterol (146짹34mg/dL vs. 109짹23mg/dL, p<0.001) than normolipidemic patients, whereas there were no significant differences between 2 groups in terms of other conventional cardiovascular risk factors, diagnosis, and angiographic findings. Gray scale IVUS data showed no significant differences between 2 groups with regards to remodeling index, lesion length, plaque volume, plaque area, and plaque burden. Dyslipidemic patients had higher necrotic core volume (1.23짹0.85mm³/mm vs. 1.02짹0.80mm³/mm, p=0.029) as well as percent necrotic core volume (20.5짹8.5% vs. 18.0짹9.2%, p=0.016) than normolipidemic patients. At the minimal lumen site, percent necrotic core area was higher (21.4짹10.5% vs. 18.4짹11.3%, p=0.019) and necrotic core area was also higher (1.63짹1.09mm² vs. 1.40짹1.20mm², p=0.080) than mormolipidemic patients. Conclusions: Dyslipidemia is related with increased necrotic core content in coronary artery plaque. This study suggests that dyslipidemia plays a role in making plaque more complex, which contains large necrotic core area in coronary artery disease.