The pathological findings in two cases of neonatal citrullinemia are reported. One patient survived for eight months with treatment using alpha keto-analogues of essential amino acids. The untreated patient expired at eight days of age. Necropsy findings in these two cases are compared. The major histopathological changes were present in the brain and liver. They were much less prominent in the treated patient. Changes in a section of rib from the untreated patient were consistent with growth arrest and suggest than damage may occur in utero in neonatal citrullinemia.