Gonzales MM, Wang CP, Quiben M, et al. - Given that cognitive decline and gait speed slowing are independent predictors of disability and mortality, researchers identified joint trajectories of cognition and gait speed within an aging bi‐ethnic cohort of Mexican Americans and European Americans. The sample consisted of 182 Mexican Americans and 188 European Americans (aged 65 to 74) who were followed over a mean of 9.5 years. Cognition was evaluated with the Mini‐Mental State Examination and gait speed was investigated with a timed 10‐ft walk. Relatively stable cognition and gait (termed stable cognition and gait class, 65.4%), deteriorating cognition and gait (termed cognitive and physical vulnerability class, 22.2%), as well as stable cognition and deteriorating gait (termed physical vulnerability class, 12.4%) were identified three latent trajectory classes. Mexican American ethnicity, age, income, education, and diabetes were correlated with the chances of classification in the cognitive and physical vulnerability class vs stable cognition and gait class. The chances of classification in the physical vulnerability class was linked to female sex and body mass index. The cognition and gait speed trajectories were generally parallel, indicating the two domains may act synergistically to shape important health outcomes. Socioeconomic inequalities and Mexican American ethnicity independently gave rise to the risk of accelerated decline.