The aim of this study was to investigate the prevalence of metabolic syndrome in older people in Taiwan. This was a hospital-based, cross-sectional study. We retrospectively analysed subjects receiving self-referred health examination at one medical centre in Taiwan from 2000 to 2004. In all, 696 older people without any acute illness were enrolled in this study, 352 men (50.6%) and 344 women (49.4%). The mean age was 70.2 +/- 4.6 years (age range 65-87). Metabolic syndrome was estimated according to the criteria proposed by National Cholesterol Education Program Adult Treatment Panel III in 2001 and by International Diabetes Foundation in 2005, with the cut-off values of the waist circumference greater than or equal to either 90 or 80 cm for men or women, respectively. Among this group, 94% of the individuals presented with at least one condition of metabolic syndrome. The prevalence of metabolic syndrome defined by National Cholesterol Education Program Adult Treatment Panel III was 44.1% and was higher in women than in men (52.6 vs 35.8%, P < 0.001). Defined by International Diabetes Foundation, the prevalence was also 44.1% and was higher in women than in men (55.5 vs 33.0%, P < 0.001). The prevalence of metabolic syndrome remains relatively high in Taiwanese older people.