A variety of neoplasms can develop in each fetal organ. Most fetal neoplasms can be detected by ultrasonographic examination. Cancer appearing either at birth or within the first month of life occurs in 36.5 per million liveborn infants. The death rate is 6.24-7.6 per million live births. This article briefly reviews the sonographic findings in the most common fetal neoplasms and presents the authors' experience in the prenatal ultrasonographic diagnosis of fetal neoplasms: intracranial fetus-in-fetu, adrenal neuroblastoma and mesoblastic nephroma.