Background and Objectives: Severe non-variceal gastrointestinal bleeding is a life-threatening condition with complicated treatment if endoscopic therapy fails. In such cases, transcatheter arterial embolization is recommended. The technical and clinical effects of this technique were analyzed in this group of patients, as well as its complication rate and 30-day mortality. Materials and Methods: Patient data over a one-decade period (from 2010 to 2019) were analyzed retrospectively; 27 patients (18 men and 9 women; median age 61 years) treated by endovascular embolization in our institution, with clinically significant gastrointestinal hemorrhage after unsuccessful or impossible endoscopic treatment, were identified, and their data were collected. Results: The source of bleeding was found in 88% of patients, but embolization was performed in 96% of them. The overall technical success rate was 96.8%, and the clinical success was 88.5%. Re-bleeding occurred in eight cases, five of whom had re-embolization that was technically successful in four cases. The incidence of re-bleeding was significantly higher in patients with two or more comorbidities (p = 0.043). There was one serious complication (4%) in the group, and minor difficulties occurred in 18% of patients; 30-day mortality reached 22%. Mortality was significantly higher in the group of patients with re-bleeding (p = 0.044). Conclusions: Transcatheter arterial embolization is a mini-invasive method with high technical success in patients with endoscopically untreatable gastrointestinal bleeding; it is also suitable for high-risk cases. Mortality (to a significant extent) depends on the occurrence of re-bleeding and the patient’s comorbidities.