Fryns syndrome is a lethal, autosomal recessive syndrome of multiple congenital anomalies described by Fitch et al. in 1978 and Fryns et al. in 1979. As originally described, the major diagnostic criteria included abnormal facies; small thorax with widely spaced, hypoplastic nipples; distal limb and nail hypoplasia; and diaphragmatic hernia with pulmonary hypoplasia. Malformations involving other systems occurred irregularly in published reports. We reviewed 41 published cases of Fryns syndrome and added 4 cases of our own. The major diagnostic criteria described by Fryns were consistent in all cases with the exception of two criteria. Narrow thorax with hypoplastic nipples and gastrointestinal anomalies were present in less than 50% of the cases. Although for 16 of the 41 published cases there was no information on central nervous system findings, 21 of the 29 remaining cases (72%) had CNS malformations. These lesions were absence of corpus callosum, arhinencephaly, and heterotopia of cerebral and cerebellar tissue. Similarly, for 12 of the 41 published cases there was no information on cardiovascular findings but 29 of the 33 remaining cases (88%) had congenital heart disease. These lesions were ventricular septal defects, arterial septal defects, and persistent left superior vena cava. We conclude that central nervous system anomalies and congenital heart disease should be added to the major diagnostic criteria of Fryns syndrome.