We report a unique case of eosinophilic cystitis causing intraperitoneal bladder perforation in a child diagnosed by chance with no signs or history of trauma. To our knowledge, this is the first case of eosinophilic cystitis complicated by bladder rupture in children. The patient was successfully treated with primary repair. For children with non-traumatic bladder perforation, eosinophilic cystitis must be considered in the differential diagnosis.