Osseous choristomas are benign lesions. They are well-circumscribed and composed of compact bone with haversian systems. Lingual osseous choristomas are commonly located on the posterior third of the dorsal tongue. The pathogenesis of osseous choristomas may be as a developmental malformation or a reactive lesion after local trauma or irritation. Most osseous choristomas are asymptomatic. Treatment of osseous choristomas is simple excision. A 57-yearold Taiwanese woman had a posterior tongue mass detected incidentally during a gastroendoscopic examination. An intraoral examination revealed a pedunculated, well-circumscribed mass measuring 1 cm in diameter grossly located on the posterior one-third of the dorsal tongue. It was a firm, non-tender mass, that was fixed to the underlying tissue. An excisional biopsy was performed, and the histopathology examination revealed an osseous choristoma.