Aging is associated with insulin resistance, which represents a common factor in age-related diseases. We aimed to determine the role of 17beta-estradiol on insulin sensitivity and memory during aging using ovariectomized rats (2-26 months of age) treated with physiological doses of 17beta-estradiol. Our results indicate a lack of effect of 17beta-estradiol replacement on spatial memory assessed in a water maze. Conversely, estradiol treatment improved insulin sensitivity in aging rats. These data imply that relatively low doses of 17beta-estradiol may have beneficial effects on glucose homeostasis due to the protective effects of estrogen. However, estradiol treatment used in the present study did not prevent memory impairment associated with aging.