Objective : Congenital masses are associated with anincreased risk for perinatal complications and death;therefore prenatal imagining studies are fundamental todetermine the optimal postnatal interventions. Herein weevaluate the usefulness of the prenatal ultrasonography indetermination of congenital masses. Method : Nineteen newborn babies with mass wereenrolled in this retrospective study. Data of theultrasonographic diagnosis, gestational age at diagnosis,survival, and histological confirmation of the disease werereviewed. Results : Of the 19 newborn babies (8 male and 11 female)with mass, 13 p atients were diagnosed prenatally (68%).The location of the masses were abdominal (n: 12), thoracic(n: 6) and cranial (n: 1). The ratio of prenatal diagnosis ofabdominal, and thoracic mass was established as 10/12(83%), 3/6 (50%), respectively. The intracranial mass couldnot be detected in the prenatal period. Definitive diagnosisof the prenatally detected masses were teratoma in 4patients, ovary cystadenoma in 2 patients, Wilms tumor in2 patients, neuroblastoma in 1 patient, and rhabdomyomain 1 pa tient. The remaining 3 patients had variety of masses(mesenteric cyst, gastroenteric cyst, lymphangioma). Conclusion : Our data shows that abdominal and cysticmasses are more easily detected during prenatal periods byultrasonographic examination.