Inflammatory myofibroblastic tumor is a reactive proliferation of myofibroblasts that rarely involves the urinary bladder. The cause of inflammatory myofibroblastic tumor is unknown but may represent an initial reactive process to an infectious agent or trauma that transforms into neoplastic growth. Cases reported in children, however, often lack any preexisting bladder pathology. The authors present a case in a young child that presented as acute abdominal pain. In general, these tumors follow a benign clinical course after resection, although close monitoring is essential given the rarity of this bladder lesion.