Objective To assess and compare chemical and immunochemical fecal occult blood tests (FOBTs) in diagnosis of gastrointestinal hemorrhage and their clinical significance. Methods The FOBT was carried out in 4474 in-patients, out-patients or subjects who had annual physical examination using both hemoccult Ⅱ (CFOBT) and colloidal gold chromagraphy (IFOBT) methods.Those who was positive for FOBTs would be re-tested for 2 times and followed by gastroscopy and colonoscopy as well as other examinations in order to find the reason and location of gastrointestinal hemorrhage. Results FOBT was positive in 390 (8.22%) patients, of which 163 (41.8%) were detected by CFOBT, 100(25.6%) by IFOBT, and 127(32.6%) by both CFOBT and IFOBT. The clinical, endoscopic and other examinations revealed that upper and lower gastrointestinal bleeding were found in 235 (60.3%) and 136 (34.9%) patients, respectively. The detective rates of upper and lower gastrointestinal bleeding were 90.2% and 67.6% by CFOBT respectively, and 42.5% and 93.4% by IFOBT, respectively. The obvious gastrointestinal bleeding could be detected by both CFOBT and IFOBT. The diseases related to gastrointestinal bleeding involved acute gastric mucosal lesion, peptic ulcer, gastric cancer and colonic polyp,colorectal cancer and piles, etc. Conclusions It is demonstrated that FOBT is still important in screening and diagnosis of gastrointestinal hemorrhage.The CFOBT is superior to IFOBT in detecting upper gastrointestinal bleeding, whereas the IFOBT is superior to CFOBT in detecting lower gastrointestinal bleeding.