Introduction Projected dementia incidence in Latin America and the Caribbean for the next decades is overwhelming. Access to local data, stratified by sex, is imperative for planning precise dementia-prevention strategies. Methods We analyzed the individual and overall weighted population attributable fraction (PAF) of nine modifiable risk factors for dementia, in dementia-free subjects >= 45-years-old, using the 2016-2017 Chilean National Health Survey. Results The overall weighted PAF for modifiable risk factors was 45.8% (42.2% to 49.3%). Variables with the highest PAF were lower education, high blood pressure, hearing loss, and obesity. Women showed a greater overall weighted PAF: 50.7% (45.3% to -56.1%), compared to men: 40.2% (35.4% to 45.0%), driven by a higher PAF for physical inactivity and depression in women. Discussion The PAF for modifiable risk factors for dementia in Chile is higher than in previous world reports, due to a greater prevalence of cardiovascular risk factors. Women have a higher potential for dementia prevention. HIGHLIGHTS The proportion of dementia associated to modifiable risk factors in Chile is 45.8%. The main modifiable risk factors are high blood pressure, obesity, and hearing loss. Women had a greater prevalence of physical inactivity and depression than men. Chile had a greater prevalence of metabolic risk factors than other world regions.