A large health screening program in Taiwan with members who have periodic checks provides an opportunity to track individuals who are healthy at baseline for the emergence of the metabolic syndrome (MS) and its component disorders. The syndrome comprised abdominal obesity assessed by waist circumference, high fasting serum glucose (FSG), high triglyceride (TG), low high density lipoprotein-cholesterol (HDL-C) and high blood pressure. A cohort of 9,785 adults (4,707 men and 5,078 women), aged 19 to 84 years, who were free from the MS at baseline were followed for 4 years from 1998 to 2002. Using Asian criteria for abdominal obesity and reducing the threshold for FSG from >or=110 mg/dL to >or=100 mg/dL, the incidence of MS during the 4-year follow up in the MJ Health Screening Center Study in Taiwan was 12.7% (17.5% for men and 8.3% for women). The incidence of the MS in men exceeded that for women up until 50-59 years and then this gender was reversed in the older age groups pointing to pre-menopausal protection in women. The most evident manifestations of the incident of metabolic abnormalities were high FSG, high blood pressure and high TG, particularly in post-menopausal women. Baseline body mass index and age were the most significant predictors of MS for both men and women, with cigarette smoking significantly predictive in men. Incident information should inform preventive and intervention strategies in Taiwanese, both Chinese and Indigenous, more effectively than MS and its component disorder prevalences.