Abstract: Objective To evaluate the efficiency of 5 diagnostic modalities for hematochezia in emergency. Methods Data of patients who visited our Department of Emergency due to hematochezia between January 2007 and February 2011 were reviewed. The rates of positive findings as detected with single or combination of colonoscopy, gastroscopy, capsule endoscopy, double-balloon enteroscopy and computerized tomography were calculated and compared. Results Among these patients, colonoscopy was the important and common modality that definitely led to identification of etiology in most of the time. The rate of positive findings was 84.62% in 169 patients who underwent colonoscopy alone, 89.39% (160/179) in those who underwent colonoscopy, gastroscopy and capsule endoscopy, 94.41% (169/179) who underwent colonoscopy, gastroscopy and double balloon enteroscopy, 96.65% (173/179) in those who underwent colonoscopy, gastroscopy, capsule endoscopy and double balloon enteroscopy, and 96.72% (177/183) in those who underwent all of the 5 diagnostic modalities. The rate of detection with multi-modality diagnosis was significantly different as compared with use of colonoscopy alone (all P<0.01). Conclusions Colonoscopy is the important and common modality for etiological diagnosis of hematochezia. In patients with causes unexplained by colonoscopy, combined use of multi-modality diagnosis may help improve the rate of positive detection.