Objectives: We explored the links between chronic diseases and cognitive ability using datasets of community-dwelling older adults from Brazil, Chile, Mexico, and Uruguay from the SABE (Health, Well-Being, and Aging) survey. Methods: Ordinary least squares (OLS), Tobit and linear probability models, adjusting for extensive health and socio-demographic factors, were implemented separately for men and women and complemented by a series of robustness checks. Results: We find a negative association between the number of chronic conditions and cognitive decline that has the following characteristics: (a) differs across gender, (b) increases with the number of chronic conditions, (c) is larger among those individuals in the bottom of the cognitive distribution, (d) and is different across types of chronic conditions. Discussion: These results suggest that returns from preventive policies to reduce cognitive decline would increase if they were targeted to seniors with chronic conditions and implemented before the impact from multiple comorbidities makes the cognitive decline too steep to be reversed.