Abstract Background: With this study, we aim to describe the associations of the different categories of the Body mass index (BMI) with ADL and cognitive performance in Colombian and South Korean older adults living in the community. Methods: A cross-sectional analysis of two surveys were analyzed; Survey on Health, Well-Being, and Aging in Colombia (SABE) (n= 23448 ) and Korean Longitudinal Study of aging (KLoSA) (n= 4501 ). Participants older than 50 years were selected from rural and urban areas achieving a representative sample. Here we investigate the association between BMI categories with function, using zero-inflated negative binomial regression, and cognition, using a logistic regression model. Results: In Colombia, underweight was associated with an impaired score on the MMSE and worse performance in the IADL. Being overweight was associated with better scores on the MMSE and the IADL. For both outcomes education was highly influential. In Korea, after adjustments, there were no significant associations for any of the outcomes. Conclusions: In Colombian population, underweight, in particular, seems to be negative to preserve both cognitive and daily functioning. Additionally, being overweight but not obese was associated with less cognitive impartment and better daily functioning.