Lower limb movements and urologic systems were evaluated by prenatal ultrasound in 120 fetuses with either neural tube defects or intracranial anomalies. Despite anticipated major lower extremity and bladder dysfunction, lower limb movements were seen in 100% of the fetuses with anencephaly and encephaloceles, 93% with isolated spina bifïda, 60% with complex spina bifida and 90% with abnormal intracranial findings. In all the cases except those with cloacal exstrophy, fetal bladder and collecting systems appeared normal. Therefore, fetal lower limb movements and urinary tract integrity appear to have no diagnostic or prognostic value in fetuses with neural tube defects or other central nervous system anomalies. These diagnoses can only be made by direct ultrasound observation of the lesion itself.