OBJECTIVES Describe the prevalence of metabolic syndrome, and its association with contemporary lifestyle factors. SUBJECTS AND METHODS In 2004-2005, 4,296 subjects of the 1982 Pelotas Birth Cohort were evaluated, and metabolic syndrome (MetS) was assessed in 3,599 according to the NCEP-ATP III and IDF criteria. RESULTS Prevalence of MetS was 5.9% and 6.7% for NCEP-ATPIII and IDF, respectively. Smoking, alcohol intake, and physical activity were not associated with MetS. Among men, the body mass index (BMI) was associated with MetS - overweight [RR: 3.14 (95% CI, 1.97-5.00)] and obese subjects [RR: 17.41 (95% CI, 11.85-25.60)]. In women, family income and schooling were inversely associated with MetS, overweight increased the risk of MetS 7.73 (95% CI, 3.65-16.38) times and obesity 40.67 (95% CI, 20.85-79.33) times. CONCLUSIONS MetS was more prevalent among men according to NCEP-ATP III criteria, and obesity was the main risk factor.