Fetal tumors lead to serious illness or even death in the fetal or neonatal period. Problems vary from severe hydrops to underdevelopment of fetal organs. In some instances a tumor may cause mechanical obstruction during the birth process. Polyhydramnios frequently develops. Adequate prenatal diagnosis is of utmost importance. Timely detection of the fetal tumor prevents traumatic birth and postnatal care and treatment can be scheduled. This report is a review of the relevant recent literature and the tumors detected in our ultrasound unit between 1982 and 1988. The ultrasonographic appearance, clinical course, and differential diagnosis of the tumors are discussed.