Jejunoileal involvement of non-Hodgkin's lymphoma (NHL) is an important diagnostic factor in determining optimal treatment strategies. Here, we used double-balloon enteroscopy (DBE) to detect jejunoileal involvement of NHL and studied its clinical significance in a series of patients with NHL. Adults aged between 18 and 85 years with infiltration of the stomach, duodenum, or colon confirmed by gastrointestinal endoscopy or colonoscopy, suspected jejunoileal involvement determined by CT or FDG-PET, or any other gastrointestinal symptoms, were eligible for inclusion in the study. Among 428 patients with histologically confirmed NHL between 2004 and 2011, 83 were eligible for DBE, but 20 patients were excluded due to rejection or poor clinical status. Thus, 63 underwent DBE. The 3-year overall survival rate was significantly lower in patients with (n = 33), than without (n = 30) jejunoileal involvement of NHL confirmed by DBE (49 vs. 92 %, p < 0.005). Four participants developed aspiration pneumonia, but recovered after treatment with antibiotics.