Epignathus teratomas are rare tumors that originate in the region of the palate or pharynx and are known as Rathke pouch. They may be associated with other malformations such as a cleft palate and bifid tongue or nose. The prenatal diagnosis can be established by two-dimensional ultrasonography showing a heterogeneous mass protruding through the mouth of the fetus. The three-dimensional ultrasonography in rendering mode permits better understanding of this anomaly by the parents, facilitating the counseling. The importance of prenatal diagnosis lies in the fact that this tumor may obstruct the airways, thus leading to death at birth due to respiratory insufficiency. We report a case of prenatal diagnosis of epignathus teratoma in the 30th week of pregnancy by two-dimensional ultrasonography. We focus on the importance of threedimensional ultrasonography in rendering mode for demonstrating the spatial relationships of the tumor with the oral cavity and provide correlations between the ultrasound images and the anatomopathological findings.