Background and purpose <p>Our study assesses the association between cumulative handgrip strength and longitudinal changes in cognitive function and daily functioning.</p> Methods <p>Two comparative cohort studies were used, including the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE). Cumulative handgrip strength was calculated using three repeated measurements of handgrip strength. Linear mixed regression models evaluated the association between cumulative handgrip strength and longitudinal changes in cognitive function and daily functioning. Cox regression models were performed to determine the association between cumulative handgrip strength and the risk of cognitive and functional impairment.</p> Results <p>Individuals with lower levels of cumulative handgrip strength had lower global cognition (<i>β</i>: -0.244; 95% CI: -0.317, -0.170 for ELSA and -0.359; -0.406, -0.311 for SHARE) and experienced a faster decline in cognitive function over time (-0.025; -0.037, -0.013 for ELSA, and -0.019; -0.026, -0.013 in SHARE). We found lower levels of cumulative handgrip strength were associated with lower daily functioning (<i>β</i>: 0.267; 95% CI: 0.161, 0.374 for ELSA and 0.153; 0.079, 0.227 for SHARE), and a faster decline in daily functioning over time (0.105; 0.081, 0.129 for ELSA and 0.217; 0.195, 0.238 for SHARE). Furthermore, lower levels of cumulative handgrip strength were related to a higher risk of cognitive and functional impairment.</p> Conclusions <p>Our study suggested that lower levels of cumulative handgrip strength was related to an accelerated decline in cognitive function and daily functioning. Persistently strengthening muscle strength should be emphasized in preventing neurodegenerative disorders and disabilities.</p>