© 2014 Nova Science Publishers, Inc. All rights reserved. Gastrointestinal bleeding may be acute, presenting with hematochezia or hematemesis, or occult with only unexplained anemia or hemoccult positive stool. Management of gastrointestinal bleeding depends on the location and acuity. Diagnostic imaging studies to assess patients for acute and obscure gastrointestinal bleeding can be used to triage patients to the appropriate therapeutic intervention, whether it be surgery, endoscopy or angiography. This paper will briefly define acute and obscure gastrointestinal bleeding and review the common diagnostic imaging modalities, including radionuclide imaging, CT angiography, CT enterography, and catheter-directed mesenteric angiography, with an emphasis on CT diagnosis of gastrointestinal bleeding.