Studies in industrialized nations suggest that severe edentulism correlates with cognitive impairment, but there is little information on this association in underserved populations. We conducted a community-based study to assess whether edentulism associates with cognitive impairment in elders living in rural Ecuador. Atahualpa residents aged ≥60 years were identified during a door-to-door census and evaluated using the Montreal Cognitive Assessment (MoCA). Persons were classified into two groups according to whether they have severe edentulism (<10 remaining teeth) or not. In addition, a questionnaire allowed self-rating of oral health. A total of 274 persons (mean age 69.6 ± 7.7 years; 59% women) were included. Persons with <10 remaining teeth (n = 116) have significantly lower MoCA scores than those with ≥10 teeth (n =158), after adjusting for demographics, cardiovascular risk factors, depression and dementia (β = -1.06, p = 0.03). Self-rated poor oral health was more prevalent among persons with <10 teeth (p < 0.0001), but did not correlate with MoCA scores (good vs. poor, β = -0.89, p = 0.89). Severe edentulism is associated with poor cognitive performance in elders living in rural Ecuador. Public health campaigns directed to improve oral health may facilitate early recognition of persons with cognitive impairment in underserved populations.