OBJECTIVE Diverticular bleeding can occasionally cause massive bleeding that requires urgent colonoscopy (CS) and treatment. The aim of this study was to identify significant risk factors for colonic diverticular hemorrhage. METHODS Between January 2009 and December 2012, 26,602 patients underwent CS at our institution. One hundred twenty-three patients underwent an urgent CS due to acute lower gastrointestinal hemorrhage. Seventy-two patients were diagnosed with colonic diverticular hemorrhage. One hundred forty-nine age- and sex-matched controls were selected from the patients with nonbleeding diverticula who underwent CS during the same period. The relationship of risk factors to diverticular bleeding was compared between the cases and controls. RESULTS Uni- and multivariate conditional logistic regression analyses demonstrated that the use of nonsteroidal anti-inflammatory drugs (odds ratio [OR], 14.70; 95% confidence interval [CI], 3.89 to 55.80; p<0.0001), as well as the presence of cerebrovascular disease (OR, 8.66; 95% CI, 2.33 to 32.10; p=0.00126), and hyperuricemia (OR, 15.5; 95% CI, 1.74 to 138.00; p=0.014) remained statistically significant predictors of diverticular bleeding. CONCLUSIONS Nonsteroidal anti-inflammatory drugs, cerebrovascular disease and hyperuricemia were significant risks for colonic diverticular hemorrhage. The knowledge obtained from this study may provide some insight into the diagnostic process for patients with lower gastrointestinal bleeding.