Two patients with orbital hypotelorism, flat nose, and bilateral lateral cleft of lip and palate with a hypoplastic philtrumpremaxilla Anlage are described. Both patients had holoprosencephaly (arhinencephaly), a brain defect characterized by an arrest in prosencephalic cleavage with no or incomplete proplasia of frontal poles and olfactory bulbs. The two patients are an intermediate stage in a graded series of median facio-cerebral malformations which begins with cyclopia, and then, as face and brain transform toward normality, extends through ethmocephaly, cebocephaly, median cleft lip, and the two patients presented here. The facies of these patients are diagnostic of the type of brain malformation. Careful attention to face-brain relationships will significantly extend the number oif diagnostic facies which currently can be recognized. Physiological defects include poikilothermia, apnea, seizures, rigidity, and lack of psychomotor development. Useful diagnostic studies include skull roentgenograms to show orbital hypotelorism and absent crista galli, electroencephalography, dermatoglyphics, chromosome studies, and sometimes pneumoencephalography. Some holoprosencephalic patients, such as our first patient, who have few or no extracephalic malformations, have a 46 chromosome karyotype. Others, such as Patient 2, have many extracephalic anomalies. The literature suggests that the latter patients are apt to have 13-15 trisomy. The face predicts the holoprosencephalic brain irrespective of extracephalic anomalies or karyotype.