Objective: How are trajectories of mobility limitations (MLs) among older adults associated with mortality? Do social factors modify these associations? Method: Group-based trajectory modeling was used to identify four trajectories of MLs over a period of 4.5 years among 3,055 older Danes. Mortality analyses were conducted using additive hazard regression models. Results: Compared to older adults without MLs, older adults with high level of MLs who experienced further increase in MLs were associated with the most additional deaths followed by older adults with no MLs at baseline who later experienced limitations and older adults with a medium ML level at baseline who later experienced further increase in limitations. Men and 80-year olds experienced more additional deaths following adverse ML trajectories than women and 75-year olds. Discussion: Trajectories that led to higher ML levels were associated with most additional deaths especially among men and in the oldest age group.