[eng] Introduction: Metabolic syndrome (MS) is a clinical entity whose prevalence is increasing worldwide. It is a multifactorial condition that increases cardiovascular risk. The aim of this study is to assess the influence of sociodemographic variables and healthy habits on the appearance of MS. Material and methods: Descriptive and cross-sectional study in 418.343 Spanish workers in which the influence of sex, age, social class, educational level, physical activity, adherence to the Mediterranean diet and tobacco consumption on the prevalence of metabolic syndrome was assessed by applying three different criteria: NCEP ATPIII, IDF and JIS. Results: Multivariate analysis showed that the variables that most increased the risk of presenting MS were sedentary lifestyle, low adherence to the Mediterranean diet and age. Of all the variables analyzed, the only one that showed no influence was social class. Conclusions: In our study, all the variables analyzed except social class increased the risk of MS, of which the most influential were low physical activity, low adherence to the Mediterranean diet, and age.