Objectives-To analyze the imaging manifestations of common fetal oral masses by ultrasound combined with magnetic resonance imaging (MRI) and to discuss their differential diagnoses.Methods-A retrospective study of 6 fetuses with oral masses was performed at a tertiary referral center. The imaging features of prenatal ultrasonography and MRI in the diagnosis of fetal oral masses were analyzed.Results-Histopathological examination and/or postpartum ultrasound revealed lymphangioma malformation in 2 fetuses, and mucosal retention cyst, mature teratoma, immature teratoma, and cranial meningocele in 1 fetus, respectively. The teratoma had a characteristic sonographic appearance. In our study, the 4 cases of cystic masses did not have an abnormal vessel architecture. Supplemental MRI revealed a mass effect at the level of the hypopharynx, and in 2 cases with polyhydramnios, the mass obstructed the fetuses' upper airway. Thus, exutero intrapartum therapy surgery was performed to secure the newborn's airway.Conclusions-Oral fetal tumors represent rare congenital malformations. This study shows that a prenatal diagnosis of oral masses is feasible by ultrasound examination. MRI can further confirm the results of ultrasonography and clearly show the relationship between the mass and the hypopharynx. Ultrasonography combined with MRI could, to a large extent, facilitate early detection and appropriate treatment and improve outcome.