Do supportive personal relationships increase subjective life expectancy? The objective existence of family relationships and the subjective sense of having someone to call on in need may increase the length of life a person expects by creating assurance about the future, by reinforcing healthy habits, and by improving current health. Using the 1995 Aging, Status, and Sense of Control representative sample of 2,037 Americans ages 18-95, we find that having adult children and surviving parents increases the length of life one expects, but young children in the home does not, and marriage only contributes years of life expected for older men. People expect to live longer when they report high levels of emotional support, and the association is mediated entirely by the perception that one has someone to call on when one is sick. People with informal health support expect to live longer than those without it, and this is especially true for persons with physical impairments. Although informal health practices shape subjective life expectancy, they explain little of the effects of supportive relationships. People who smoke, drink heavily, and have poor nutritional habits expect shorter lives, and those who walk and exercise expect longer lives. Better current health is associated with higher subjective life expectancy, but it does not explain the impact of supportive relationships. Most of the impact of supportive relationships appears to be a direct result of projected security about the future. Feeling that you have someone who would care for you if sick appears to increase the sense of security about surviving future health crises, thereby increasing one's perceived inventory of the essential property--life itself.