Objective Researchers have consistently shown that providing care in a gradually deteriorating situation, such as dementia, can be stressful and detrimental to the caregiver's (CG) health. Although stressor appraisal is important in understanding variability in CG outcomes, the role of personal mastery, a coping resource, in shaping CG's health outcomes has not been considered. The primary goal of this paper was to determine whether personal mastery is associated with a survival advantage for spousal CGs of persons with dementia. Methods This study assessed the association of CG burden and personal mastery with longevity over a 10-year period in 71 spousal CGs of persons initially diagnosed with mild cognitive impairment. Results Over the 10 years, 16 of 71 CGs (23%) died. Cox regression models with right censoring of CGs' time to death showed that after adjusting for the health of family CG, spousal CGs who reported high levels of burden had an 83% reduced risk of death when they also reported high personal mastery (hazard ratio [HR] = 0.17, 95% confidence interval [CI] 0.04, 0.65). Conclusions Findings have implications for support programs that help build personal mastery.