Background: Personality has been shown to be related to numerous health-related factors. In the SNAC-B study, relationships between health variables and the personality traits of neuroticism (N), conscientiousness (C), agreeableness (A), openness (O), and extraversion (E) have been investigated. Aim: In this chapter, stability and change of personality during the ages of 60 to 90 years are explored. In addition, relationships between personality traits and health-related variables are presented. Methods: The results are based on data from the SNAC-B studies of 1402 men and women aged 60 to 90. The participants have been followed up during 12 years, while data on health, well-being, and autonomy have been continuously collected. In addition, variables assumed to influence health have been collected, such as lifestyles, demographic factors, social environment, and personality. Results: The results show personality to be stable over time according to rank order, but all personality traits except neuroticism were shown to have small but significant mean level changes. In addition, connections between a number of health-related variables and personality traits, such as mortality, self-care, work ability, and perception of pain, were indicated. Conclusions: The results indicate that the role of personality should be taken into account in research on health and aging. Personality traits have a lifelong influence on health behaviors and have been shown to affect both subjective and objective aspects of health and the way we cope with health-related experiences.