The Framingham Heart Study was begun in 1948 to study factors associated with cardiovascular disease. Participants have been reexamined approximately every two years. From 1973 to 1975, the Framingham Eye Study examined the eyes of available Heart Study participants. We used information about nearly 2000 persons from these population-based studies to investigate the relation of lens changes to survival. Follow-up ranged from five to eight years; 312 persons (16 per cent) died. Proportional-hazards regression analyses indicated an overall association of lens changes and decreased survival (P = 0.01), but detailed investigation showed (1) no association of lens changes and decreased survival among persons without diabetes (P = 0.29) and (2) a significant association of lens changes and decreased survival among persons with diabetes (P = 0.001). Diabetic persons with lens changes had an estimated death rate more than twice that of diabetics without lens changes. The duration of diabetes and degree of retinopathy were not associated with survival in this group, most of whom had adult-onset diabetes of short duration. We conclude that lens changes are earlier predictors of death in diabetics than these more traditional variables.