Eosinophilic colitis is a rare inflammatory disease characterized by eosinophilic infiltration of the colon and peripheral blood eosinophilia. We report on a case of eosinophilic colitis in a 29-year-old woman with acute myeloid leukemia following allogeneic bone marrow transplantation from her HLA-identical sister. To our knowledge, eosinophilic colitis has rarely been reported in association with allogeneic bone marrow transplantation.