The effect of angiotensin II antagonist, losartan, on chronic stress-induced elevation of blood glucose levels was investigated in rats. Chronic immobilization stress caused an increase in blood glucose levels in rats. Administration of losartan (3 mg/kg, po) before stress exposure significantly prevented this increment. We suggest that losartan showed this effect by decreasing the excessive sympathetic response to stress. In conclusion, there is a relationship between stress, sympathetic nervous system, and reninangiotensin system.