Analysis of mortality estimates and adjusted census data showed that men aged 70 to 79 married to younger women tended to live longer than men married to older women. The standard mortality ratio for 50-year-old husbands with younger wives was 90, whereas it was 112 for husbands with older wives. For 70-year-old men the comparable values were 80 and 133. Thus the mortality risk associated with marriage to a younger woman was clearly less than that associated with marriage to an older woman. Two possible explanations were advanced for this relationship: (a) premarital selection factors may be related to longevity, and (b) psychological, physiological, or social factors associated with longevity may be enhanced by marriage to a younger woman.