Walking activity has been associated with reduction in the development of chronic disease, cognitive and physical function impairment, disability, and mortality. The objective of this study was to examine the relationship between walking activity and physical function over 9years of follow-up among Mexican Americans aged 78years and older. Participants (N = 998) were from the Hispanic Established Population for the Epidemiologic Study of the Elderly (2007-2016). Measures included walking activity duration and frequency, socio-demographics, body mass index, medical conditions, pain, depressive symptoms, limitation in activities of daily living, and the Mini-Mental State Examination. Low physical function was defined as scoring <7 on the Short Physical Performance Battery. At baseline, participants were grouped into nonwalkers (n = 653), walked <150minutes/week (n = 144), and walked 150minutes/week or more (n = 201). A Generalized Estimating Equation model was used to estimate the odds ratio and 95% CI of low physical performance as a function of walking activity status. Compared with nonwalkers, participants walking < 150minutes/week had lower odds (odds ratio = 0.66, 95% CI, 0.51-0.86) of low physical function over time, after controlling for all covariates, as did those walking ≥ 150minutes/week (odds ratio = 0.54, 95% CI, 0.41-0.71). Mexican American older adults who engage in any walking activity are at reduced risk of low physical function, even those with disability. Interventions at the individual and community level are recommended to reduce physical function impairment, even in those with preexisting medical conditions or disability.