A 46-year-old man with no history of interest presented with recent onset iron deficiency anaemia (Hb 11.3g/dL; MCV 79.8 µ3; Urea 29 mg/dL; Creatine 0.95 mg/dL; Iron 29 µg/dL, Ferritin 12 µg/L) at a routine check-up at work. The patient denied ingestion of gastro-lesive drugs and digestive externalisation of the bleeding, so conventional endoscopic examination was indicated (gastroscopy and ileo-colonoscopy), which was negative. After 30 days, the study was completed with an ECE, which was also negative, and the study was terminated and symptomatic treatment with oral iron supplements was indicated. After 3 months, the patient attended the emergency department for asthenia and melena in the last 48 hours. On physical examination he was pale and sweaty. His blood pressure was 90/60 mm Hg and heart rate was 105 beats per minute, and a rectal examination revealed the presence of melena stools. Laboratory tests in the emergency department (Hb 7 g/dL; MCV 77.2 µ3; Urea 57 mg/dL; Creatine 0.74 mg/dL) confirmed the suspicion of gastrointestinal bleeding, and the patient was admitted for observation. In the first 24 hours, 2,000 ml of fluid therapy was administered and 4 red blood cell concentrates were transfused, with post-transfusion haemoglobin of 9.5 g/dL. Once the patient was stabilised, and given the suspicion of an upper gastrointestinal haemorrhage, an urgent gastroscopy was performed, which was negative, and a new ECE was repeated at that time. In this last examination, the origin of the bleeding was identified from a gastric lesion of submucosal origin and ulcerated on its surface that was hidden between the gastric folds. The diagnosis of certainty was obtained after a new gastroscopy and after ruling out metastatic disease, the lesion was resected. The histopathological study confirmed the submucosal origin of the lesion (gastric GIST).