Acute myelogenous leukemia (AML) can involve the gastrointestinal tract but rarely involves the appendix. We report a male patient who had 1 year partial remission from AML and who presented with apparent acute appendicitis as the initial manifestation of leukemia relapse. Pathological findings of the appendix revealed transmural infiltrates of myeloblasts, which indicated a diagnosis of leukemia. Unfortunately, the patient died from progression of the disease on the 19th d after admission. Although leukemic cell infiltration of the appendix is uncommon, patients with leukemia relapse can present with symptoms mimicking acute appendicitis.