The role of endoscopic therapy for peptic ulcer bleeding is well-documented. Nevertheless, rebleeding occurs in 10% to 30% of patients, and such patients are at high risk for death without early retreatment or definitive surgery. The aim of our study was to predict which patients would rebleed within 1 month after successful multipolar electrocoagulation of 100 patients with active peptic ulcer bleeding (spurting, oozing, or nonbleeding visible vessel). We had achieved initial hemostasis in 97 patients and carried out univariate and multivariate analyses to predict which patients would rebleed. Rebleeding occurred within 1 month in 17 (17.5%) patients. we correlated 20 clinical and endoscopic factors with rebleeding episodes. With univariate analysis, blood transfusion of 500 ml or more at entry (p < 0.0001) and use of cimetidine (p = 0.01) were statistically significant for rebleeding. With multivariate analysis, use of omeprazole was an independent factor for preventing rebleeding (odds ratio, 7.68; 95% confidence interval, 1.642-35.929). We suggest that omeprazole may help to prevent rebleeding in patients who have had hemostasis with multipolar electrocoagulation.