The rate of albumin synthesis was estimated in hepatocytes prepared from groups of rats maintained on diets of different protein content. These diets were fed either ad lib or at 50% restriction of ad lib consumption. The psysiological capacity of hepatocytes to synthesize albumin varies with dietary intake. Albumin production by cells prepared from animals fed ad lib was directly related to the protein energy:total energy ratio of the food. Restricting consumption of the control diet to 50% of ad lib intake did not reduce albumin synthesis rates, and similar restriction of the low protein diets ameliorated some of the depression in albumin production observed in hepatocytes isolated from animals fed the same diets ad lib. The results are discussed with reference to the occurrence of hypoalbuminemia in children with protein-energy malnutrition.