The detection and diagnosis of structural anomalies of the fetal central nervous system has become commonplace. Therefore, the pediatric neurosurgeon who will eventually care for a child postnatally can be called upon to interpret the meaning of diagnostic studies and advise the prospective parents prenatally. This article discusses some principals of prenatal counseling as they relate to neurosurgical conditions, reviews the diagnostic armamentarium for defining neurosurgical fetal conditions, and describes the common antenatal diagnoses that may be encountered by the neurosurgeon.