Patients with celiac disease have an increased rate of enteropathy-associated T-cell lymphoma, but conflicting data are available about the protective role of a gluten-free diet with regard to the development of this malignancy. We followed 1,757 celiac patients for a total period of 31,801 person-years, collecting data about the frequency of gluten intake and the incidence of the enteropathy-associated T-cell lymphoma. Out of the nine celiac patients who developed an intestinal lymphoma [standard morbidity ratio of 6.42 (95% CI = 2.9-12.2; P < 0.001)], only two kept a strict gluten-free diet after the diagnosis of celiac disease and developed the malignancy after the peridiagnosis period of 3 years, dropping therefore the standard morbidity ratio to 0.22 (95%CI = 0.02-0.88; P < 0.001). The risk of developing an intestinal lymphoma for the celiac patients that used to have dietary gluten was significant (X(2 )= 4.8 P = 0.01). These results show that a strict gluten-free diet is protective towards the development of enteropathy-associated T-cell lymphoma.