Objective: This study was conducted to assess the prevalence of metabolic syndrome (MetS) in Tehranian women during menopausal transition. Design: In this cross sectional study 2182 subjects, pre-menopausal (pre-M) n=537, menopausal (M) n=311 and postmenopausal (post-M) n = 1334 were selected from 15005 participants of the TLGS and assessed for MetS risk factors. All MetS components were evaluated following age adjustment according to the ATPIII criteria. Results: The mean ages of post-M, M and pre-M women were 61.0 +/- 4.3, 53.0 +/- 4.0 and 47.0 +/- 1.9 years, respectively. The prevalence of MetS in subjects was 63% (53%, 54% and 69%) in pre-M, M and post-M women respectively. HDL-c levels was significantly higher in post-M women in comparison to pre-M women (p < 0.001). TG levels, FPG and waist circumference was significantly higher in post-M women in comparison to pre-M women (p < 0.05). The most frequent markers of MetS were low HDL-c and high diastolic blood pressure in post-M women. Conclusion: It is concluded that the frequency of MetS is significantly higher in post-M women as compared to pre-M women; low HDL-c and high diastolic blood pressure is the most frequent feature in comparison to other factors. (c) 2007 Elsevier Ireland Ltd. All rights reserved.