Background: CT angiography (CTA), a minimally invasive diagnostic technique, has become popular for looking into acute gastrointestinal hemorrhages. Aim of the study: this study aimed to evaluate the validity of Computed tomography angiography (CTA) for diagnosis of the cause of acute GIB and its influence on treatment. Patients and Methods: This study was carried out in Radiodiagnosis Department, Faculty of Medicine, Zagazig University on 24 cases with acute GIB during the period from June 2023 to December 2023 on 24 patients who were acute GIB. Age > 18 years. Both male and female. were included as a comprehensive sample. Results: The most frequent diagnoses detected by CT-angiography among patients were esophageal gastric varices which was detected among (75%) of the patients, while the least frequent diagnoses detected was pancreatic arteriovenous malformations in 25% of patients. There was no significant difference between bleeding type and age or gender (P>0.05). sensitivity of CT angiography in diagnoses bleeding compared to endoscopy is (92.3%), positive predictive value (PPV) is (63.2%), negative predictive value (NPV) is (80.0%),accuracy of Ct angiography in diagnoses bleeding compared to endoscopy is (66.7%). Conclusions: CT angiography is a valid, noninvasive method that is conveniently accessible. CT angiography has a high sensitivity in identifying the source of current bleeding. The results of CT angiography are useful in guiding the best course of treatment (directed endoscopic intervention, angiographic embolization, or surgery), as well as in determining when these treatments should be carried out