To evaluate the effect of obesity on atherosclerosis, health, and longevity in the elderly, we studied the relationship between body mass index, atherosclerosis, and the duration of disability by multivariate analyses. We analyzed data from 521 residents of the Yokufu-kai home for the aged. They underwent a 50 g oral glucose tolerance test, and autopsies were done after they died. All functional evaluations were done retrospectively from the hospital records. The mean age of the time of death was significantly higher in the overweight group than in the lean group. The incidence of marked cerebral atherosclerosis was significantly higher in the overweight and the obese groups than in the lean and the medium-weight groups. The incidence of cerebral infarction with neurological deficits was significantly higher in the overweight group than in the lean group, but there were no differences in other types of infarction. The incidence of severe coronary artery stenosis was significantly higher in the obese group than in the lean and medium-weight groups, but there was no difference in the incidence of myocardial infarction between groups. There were no differences in the incidence of severe atherosclerosis of the aorta, femoral artery, or renal artery between groups. Patients in the overweight group were bedridden for a significantly longer time than those in the lean group. We conclude that body weight in the elderly is positively associated with survival. However, overweight subjects suffered from non-fatal cerebral infarction, and prolonged survival was associated with greater disability.