Ultrasound evaluation of the fetus has become a vital part of prenatal care not only to detect abnormalities of fetal growth but to diagnose congenital anomalies, hydatidiform mole and ectopic pregnancy, to assess fetal well-being, and finally to provide ultrasound guidance for invasive procedures. This article will discuss the role of fetal ultrasonography as we head into the 1990s, the changing concepts of indications for ultrasound scanning, the increasing sophistication of the technique, and the types of anomalies detected by this imaging method.