OBJECTIVE: To determine if functional health literacy (FHL) mediates the relationship between socio-economic status, and perception of the risk of lifestyle behaviors for cancer. METHODS: Cross-sectional, random population survey, 2824 people aged ≥15 years, September-October 2008, included newest vital sign measure of FHL. RESULTS: Less than adequate FHL occurred in 45.1%. People who perceived behavioral factors (smoking, diet, obesity, alcohol, physical activity) to be not important, or did not know if they were important cancer risks, were more likely to have inadequate FHL. In a logistic regression model adjusted for age, gender, education, income, occupation, country of birth and area of residence, inadequate FHL was associated with 2-3 (OR=1.9; 95% CI: 1.2-3.0) and 4 or more self-reported lifestyle risk factors (OR=2.8; 95% CI: 1.6-5.0). In a structural equation model of the relationship of socio-economic status, perceptions of risk and behaviors there was significant mediation effect of FHL on the path from SES to health perceptions, estimated 29.4% of the total effect. CONCLUSION: A specific focus on the literacy demands made on individuals from health promotion and materials with a view to improving health communication is indicated. PRACTICE IMPLICATIONS: Health literacy is important for health promotion.