The aim of this study was to evaluate the relationship between the diagnosis of metabolic syndrome (MetS) or its components and the prevalence of microvascular and macrovascular complications in 130 Japanese type 2 diabetic patients. Out of the 130 patients, 58.5% satisfied the criteria of the MetS as defined by the IDF guideline. The results of logistic regression analysis with adjustment for three variables (age, gender and duration of diabetes) revealed that the presence of MetS as defined by the IDF guideline was not independently related to the presence of proliferative retinopathy, proteinuria, neuropathy, or macrovascular disease in the diabetic patients. The waist circumference per se was not associated with diabetic neuropathy, retinopathy, nephropathy, or macrovascular diseases. These results suggest that neither the presence of MetS, as defined by the IDF guideline, nor the waist circumference was associated with the presence of either microvascular or macrovascular complications in Japanese type 2 diabetic patients.