OBJECTIVES: The aim of this study was to conduct a meta-analysis to identify the potential differences of cardiovascular risk factors between men and women in primary prevention. METHODS: A systematic review was performed identifying prospective cohorts studies in which cardiovascular risk factors were analyzed (tobacco use, hypertension, diabetes, obesity and dyslipdemia) associated to the development of acute myocardial infarction, angina pectoris or cardiovascular death, and in which results were segmented between men and women. The search was done in October 2009 in Medline, EMBASE and the Cochrane Collaboration. Two independent reviewers identified the abstracts, selected full articles and extracted the data. Relative risk(RR) with 95% confidence intervals (95%CI) were calculated. Random effects models were employed in the meta-analyses using Meta-Analyst v.2.0 software. A meta-regression was also conducted. RESULTS: From 3,712 studies, 21 cohort studies were selected. The number of participants among the trials varied between 5,000 and 600,000 per study with a follow-up from 5 to 40 years. The meta-analyses showed that premenopausal women in comparison to men had a higher risk of having cardiovascular event when they have diabetes mellitus (RR 2.79 vs. 2.03), obesity (1.62 vs. 1.41), hypercholesterolemia (1.91 vs. 1.49), increase in LDL levels (2.08 vs. 1.72) or increase in HDL levels (2.22 vs. 1.61); however, men showed higher risk of cardiovascular events when they have hypertension (RR 1.771; 95%CI 1.714–1.830 vs. RR 1.812; 95%CI 1.759–2.305). In addition, women use of contraceptives was not a significant cardiovascular risk factor. CONCLUSIONS: The majority of cardiovascular risk factors seem to be higher in premenopausal women rather than men. Preventive programs should include female population in other to avoid a greater number of cardiovascular events in the future.