The relationship between essential fatty acid (EFA) status and degree of hyperbilirubinaemia and oxidant stress in infants and children with chronic liver diseases was evaluated. Thirty patients with chronic cholestasis and 30 with liver cirrhosis were examined; 30 healthy subjects served as controls. Patient groups had significant decreases in EFAs and significant elevation of total bilirubin. Levels of thiobarbituric acid reactive substances were significantly raised and were significantly inversely correlated to decreased EFA levels. There were also significant decreases in retinol, alpha-tocopherol and alpha-tocopherol/total lipids ratio, which had significant positive correlations with decreased EFA levels. Infants and children with chronic liver diseases have a high risk of EFA deficiency correlated with progressive elevation of serum bilirubin and progressive deterioration of oxidant status.