We report a case of fine needle aspiration cytology of endodermal sinus tumor of the ovary. A 13-year-old girl complained of abdominal mass and pain. The abdominal sonography revealed a well-demarcated huge mass, which was solid and multiseptated. Percutaneous fine needle aspiration was performed from the mass. The smears revealed moderate cellularity, which was arranged in sheets or clumps of pleomorphic malignant cells on mucoid background The valuable characteristic features of tumor cells were papillary configuration, vacuolated cytoplasm and intracellular and extracellular hyaline globules. The diagnosis was confirmed later by histologic study of surgical resection of the specimen.