Visceral obesity is associated with the clustering of metabolic risk factors and the incidence of cardiovascular events. However, the association between the waist circumference values and the metabolic risk factors has not been fully established in Japanese middle-aged subjects. We examined the data from 6,033 Japanese middle-aged subjects aged 40-59 yr (4,599 male and 1,434 female). Metabolic risk factors such as high blood pressure, dyslipidemia, and glucose intolerance were identified according to the diagnostic criteria for metabolic syndrome in Japan. Numbers of metabolic risk factors were significantly associated with the waist circumference values in both male and female subjects. The prevalence of subjects with multiple (two or more) metabolic risk factors was 29.7% and 7.4% in male and female, respectively. According to receiver operating characteristic analysis, the cut-off values of waist circumference with the maximal sensitivity plus specificity to predict the presence of multiple metabolic risk factors were 86 cm and 81 cm in male and female, respectively. These values were in agreement with the diagnostic criteria for metabolic syndrome in Japanese male, but not in female. In conclusion, the waist circumference values can predict the presence of multiple metabolic risk factors in Japanese middle-aged subjects.