INTRODUCTION: Aorto-enteric fistulas (AEFs) are rare but serious causes of gastrointestinal bleeding, classified into primary and secondary types. This report describes the first documented case of a secondary AEF from Nepal, emphasizing the need for prompt diagnosis and surgical intervention. CASE PRESENTATION: A 36-year-old male presented with black tarry stools and abdominal pain, 7 years after aorto-right common femoral artery and aorto-left common iliac artery bypass surgery for common iliac artery occlusive disease. He had a history of recurrent graft infections. Examination revealed hypotension, tachycardia, and melena. Upper gastrointestinal endoscopy showed the aortic graft in the duodenum, with CECT confirming an aortic graft inside the bowel lumen, leading to a diagnosis of secondary aorto-enteric fistulas (SAEF). DISCUSSION: SAEFs often arise from graft infection and mechanical erosion by the pulsatile graft. Patients typically present with gastrointestinal bleeding, and early diagnosis is crucial, as untreated SAEFs have a mortality rate approaching 100%. The combined use of upper gastrointestinal endoscopy and CECT is essential for identifying and guiding the surgical intervention of SAEFs. This case underscores the importance of early diagnosis and early surgical intervention for successful management of SAEF. CONCLUSION: This case highlights the importance of suspecting secondary AEFs in patients with aortic graft presenting with gastrointestinal bleeding. Early diagnosis and timely surgical intervention are essential for improving patient outcomes.