In the present study, the effect of estrogen on gastric acid secretion and peptic ulcer and whether it acts through alpha or beta estrogen receptors has been investigated in a total number of 90 female albino rats divided into five groups with 18 rats allocated in each group.Results showed that gastric acid secretion and number of ulcers were significantly higher among ovariectomized group than in control group when estimated within the basal acid secretion, carbachol induced acid secretion and indomethacin induced ulcer sub groups (P<0.05).