The sex cord tumor with annular tubules(SCTAT) is a rare ovarian neoplasm, which charateristically shows simple and complex annular tubules with central acidophilic hyaline bodies. This tumor has been considered as a tumor of low-grade malignancy with late recurrence. We presented a brief case report of metastatic SCTAT of ovary in pleural fluid from ovary with cytopathologic and clinical features. The cytologic features of differential diagnosis are discussed.