Purpose. This cross-sectional study explored the epidemiology of metabolic syndrome in Taichung. Methods. We retrospectively analyzed people who had cumulatively undergone periodic health check-ups at a medical center in Taichung from January 2000 to December 2002. In total, 3053 people were enrolled in this study. The prevalence of metabolic syndrome was estimated according to the criteria proposed by NCEP/ATP Ⅲ; the criteria were modified to include abdominal obesity and the cut-offs of waist circumference (≥90 cm for men and ≥80 cm for women) in Taiwan. Data were analyzed by the t test, chi-square test and multivariate logistic regression. Results. There were 1711 men (56.0%) and 1342 women (44.0%). The mean age was 49.7±12.3 years (age range, 20 to 87 yr). Overall, the prevalence of metabolic syndrome was 25.6% (25.5% in men and 25.8% in women). After controlling for other covariates, multivariate logistic regression analysis showed that people aged 40 to 64 years and 65 years and older were more likely to develop metabolic syndrome (odds ratio=2.19 and 5.99, 95% CI=1.63 to 2.93 and 4.15 to 8.64, respectively, p＜0.001) compared with individuals aged 20 to 39 years in the reference group. We also found that overweight and obese people were more likely to develop metabolic syndrome (OR=3.45 and 8.51, 95% CI=2.70 to 4.42 and 6.51 to 11.14, respectively, p＜0.001). Other significant risk factors of metabolic syndrome included hyperuricemia (OR=1.42, 95% CI=1.17 to 1.73, p＜0.001), fatty liver (OR=2.85, 95% CI=2.32 to 3.50, p＜0.001), and alcoholism (OR = 1.47. 95% CI=1.10 to 1.98, p＜0.05). Conclusions. The prevalence of metabolic syndrome is relatively high in Taichung. We hope the results of this study will provide additional information for the development of preventive measures of metabolic syndrome in Taiwan.