Traditional imaging techniques are insufficient for diagnosis of small bowel diseases. Double-balloon endoscopy is a novel method for the diagnosis of this region. Here, we report three cases diagnosed with gastrointestinal stromal tumors by double-balloon enteroscopy, which were missed by the other imaging techniques including capsule endoscopy. In summary, double-balloon enteroscopy should be performed if there is high clinical suspicion for small bowel pathology even if the capsule endoscopy is negative.