Two siblings with Zellweger''s cerebro-hepato-renal syndrome are reported. The 2 children both had multiple anomalies associated with Zellweger''s syndrome such as characteristic facial appearance, cerebral dysfunction, muscular hypotonia, liver abnormalities, failure to thrive, marasmus and early death. One of the children, a girl, lacked several anomalies that were present in her brother. In one of the children, bile acid analysis was performed by use of gas chromatography-mass spectrometry. 3.alpha.,7.alpha.,12.alpha.-Trihydroxy-5.beta.-cholestanoic acid (THCA) and varanic acid, both precursors of cholic acid, were found. The defect bile acid synthesis may be due both to liver mitochondrial abnormalities and to the absence of liver peroxisomes, conditions known to occur in Zellweger''s syndrome.