BACKGROUND: Adiponectin is adipose tissue derived hormone, which has been shown to play an important role in the regulation of glucose and lipid metabolism. Low adiponectin levels are associated with obesity and diabetes and coronary artery disease. In addition to adiponectin level, the adiponectin multimerization and its ratio to total adiponectin have also affect on metabolic risk factors and insulin resistance. However, the adiponectin multimerization pattern in type 2 diabetes of Korean has not been established. We investigated adiponectin levels and adiponectin multimerization pattern according to obesity in type 2 diabetes males of Korean. METHOD: The subjects of this study were 86 of diabetes patients and 89 of control subjects whose fasting blood glucose was below 110 mg/dL. They were divided into two subgroup, non-obese and obese, according to BMI (non-obese 25 < BMI). Anthropometric parameter and other metabolic risk factors were measured. Insulin resistance was presented by HOMA-IR. Plasma adiponectin level was measured by radioimmunoassay method. Adiponectin multimerization was fractionated by SDS-PAGE under non-reducing and non-heat denaturing state and performed immunoblotting. RESULT: Serum adiponectin levels were significantly reduced in obese than non obese group in diabetes patients (7.73 +/- 5.2 versus 12.56 +/- 8 microgram/mL, P = 0.003). Correlational analyses demonstrated that BMI, body weight, waist circumference, diastolic pressure, glucose and height correlated significantly with adiponectin levels in the diabetes patients. The HOMA-IR did not affect the plasma adiponectin levels in diabetic patients. There were no differences in adiponectin multimerization distribution and ratio between obese and non-obese group in the diabetes, however middle molecular weight multimers (MMW, ~110~160 Kda, hexamer) ratio in the control subjects were significantly reduced in obese group than non-obese group (49 +/- 9 versus 56 +/- 11%, P < 0.05). CONCLUSION: The adipoenctin levels were lower in obese than non-obese group of diabetes males in Korea. Aiponectin levels correlated with BMI and weight but not insulin resistance. The differences of adiponectin multimerization distribution and ratio between obese and non-obese group in diabetes were not detected.