Nonleukemic myeloid sarcoma (MS) is a rare tumor that can occur in several locations without myeloid leukemia. We reported a first case of nonleukemic MS of the spleen involving the liver in a 5-month-old boy presenting with hematochezia, petechial hemorrhage, fever, and hepatosplenomegaly. Bone marrow trephine biopsy and immunophenotypic flow cytometry revealed no evidence of myeloid leukemia. The patient underwent liver biopsy and splenectomy. Clinicopathology and immunohistochemistry suggested a disseminated nonleukemic MS. The patient died of respiratory failure on the seventh postoperative day. Early diagnosis of a disseminated nonleukemic MS may be quite important for patient survival and it should be considered one of the differential diagnoses of hepatosplenomegaly with atypical clinical features.