A 54-year-old male was admitted to Kawasaki Medical School Hospital with the complaint of fever. His diagnosis of hypoplastic leukemia had been made one year ago. After the admission, cecal mass with pain and high fever were noted. Four days later, he suddenly lost consciousness and died. Aeromonas hydrophila was isolated from blood cultures and also from the myofascitis specimen. Autopsy specimen of the iliopsoas muscle showed necrotizing myofascitis. The specimen obtained from the cecum showed submucosal hemorrhage with edema and these findings were compatible to ischemic colitis. This pathogen is widely distributed in nature, especially in water fields. Therefore, it would be advised to consider the Aeromonas hydrophila as one of the pathological organisms pathognomonic for the septicemia, when one may see febrile and gastrointestinal symptoms in a patient with hematological malignancies.