We observed the occurrence of celiac disease following allogeneic bone marrow transplantation in a patient transplanted for acute leukemia. The marrow donor was his HLA-identical sister, who had suffered from celiac disease since birth. The post-transplant period was characterized by recurrent episodes of diarrhea. Detailed workup showed atrophic intestinal mucosa on histology and anti-gliadin and anti-endomysium antibodies in the serum, features that were not present before transplantation. GVHD was absent at that time. The patient remains free of symptoms on gluten-free diet and slight immunosuppression. This case suggests transmission of celiac disease by bone marrow transplantation and supports the T cell concept in celiac disease.