We investigated the effects of the oral administration of vanadyl sulphate (0.5 mg/ml in the drinking water) on glucose homeostasis of 3-month- and 24-month-old rats. Results show that aging is associated with alteration of the oral glucose tolerance test and impairment of the postprandial accumulation of glycogen in skeletal muscles and that the oral administration of vanadyl sulphate rapidly normalizes the inbalance of glucose metabolism in senescent rats. It is suggested that vanadate administration may restore the ability of skeletal muscles of senescent rats to respond to circulating insulin efficiently.