Metabolic syndrome (MS) is based on visceral obesity and insulin resistance (IR) and, shows abnormalities in fat and glucose metabolism as well as hypertension. We investigated the relationship between IR and various risk factors for atherosclerosis in 378 male subjects (averaged age: 63.8 +/- 15.2 years) and 509 female subjects (averaged age: 67.1 +/- 13.5 years) recruited from a health check examination. Homeostasis model assessment (HOMA-IR) was used as an indicator of IR. Body mass index (BMI), triglyceride (TG), remnant-like particle cholesterol (RLP-C) and C-reactive protein (CRP) showed a good correlation (r > 0.2) with HOMA-IR. LDL cholesterol(LDL-C), small dense LDL(sdLDL) and HbA1c showed less stringent (r < 0.2) but still significant correlation with HOMA-IR. In contrast, oxidized LDL (oxLDL) and systolic blood pressure did not show any correlation. A multiple regression analysis indicated that BMI, RLP-C, HDL-C, HbA1c and CRP were independently correlated with HOMA-IR. These observations suggested that, among the three new lipid parameters (i.e., RLP-C, sdLDL and oxLDL), RLP-C was the most closely related to the IR status.