Treatment of complicated giant duodenal ulcers is one of the most difficult problems in abdominal surgery. Simultaneous course of diabetes mellitus and giant duodenal ulcer has clinical features and requires correction of the treatment. It is presented case report that may be useful regarding accumulation of knowledge about comorbid course of these pathologies. The patient 58-year old was urgently delivered with signs of gastrointestinal bleeding, ulcerative anamnesis for 15 years, diabetes mellitus type 2 for 8 years. Gastroduodenoscopy revealed chronic giant (2.5×3.5 cm) duodenal ulcer complicated by bleeding and subcompensated pyloric stenosis. Endoscopic hemostasis included drug injection and argon-plasma coagulation. Recurrent bleeding occurred after 22 hours. It was performed Billroth II procedure with resection of 2/3 of the stomach and manual formation of 'difficult' duodenal stump. Cicatricial ring was used as a frame for the stump. Postoperative period was uneventful, patient was discharged after 14 days. This clinical case demonstrates the need for more active surgical strategy in patients with diabetes mellitus and reliability of the proposed method of 'difficult' stump forming.