BACKGROUND AND AIMS: It is generally accepted that enteropathy-type intestinal lymphoma (EATL) arises against a background of gluten enteropathy. We investigate whether patients with this diagnosis had celiac disease or pre-existing celiac disease, based on gliadin and endomysium antibodies, as well as duodenal biopsies, HLA typing and response to gluten-free diet. METHODS AND RESULTS: Retrospective study of patients with the diagnosis of peripheral T cell lymphoma of the intestine between January 1990 and January 2002 at the university hospital Gasthuisberg Leuven (n = 14). Patients in whom serologic testing was performed or patients known with pre-existing celiac disease (CD) were included (n = 9). Six of these nine patients were tested for endomysium antibodies (AEM), none of them were positive. Of the six patients with biopsies of mucosa uninvolved by lymphoma, all of them had villous atrophy; five had increased intraepithelial lymphocytes (IEL). In the four patients were HLA typing was performed, the results were compatible with CD. The three patients with initially diagnosed celiac disease all improved on gluten free diet (control biopsies improved as well, but failed to normalise). Of the six other patients, one patient never started GFD, two didn't get better, one initially went better after GFD, and one went better with the concomitantly started chemotherapy. CONCLUSION: There are two possible explanations: Either these patients with EATL have indeed gluten intolerance but the sensitivity of AEM is overestimated in this patient population; or these patients don't have gluten intolerance and EATL itself can mimic CD or other factors mimicking CD are at risk for developing EATL.