Abstract: Familial Intrahepatic Cholestasis (FIC) includes a heterogeneous group of recessive autosomic alterations characterized by hepatocellular cholestasis secondary to the interruption of the normal process of synthesis of bilis. Objective: A description of FIC in 3 of 5 children of an index family. Clinical case: a 5 y.o. child with hepatosplenomegaly increased serum hepatic enzymes and biliary acids. Abdominal echography showed alterations compatible with hepatic fibrosis. Biopsy showed bridge fibrosis, duct proliferation, minimal chronic cholestasis. These findings were compatible with a phenotype FIC-3 with elevate levels of Gamma-glutamyl transferase. A mutation of MDR3 gene is responsible for the absence of biliary phospholipids, allowing a detergent effect of biliary acids upon the duct epithelium, developing cholangitis, fibrosis and later cirrhosis. Among four brothers, the mutation was found in two twin sisters. Three affected brothers were treated with ursodeoxicolic acid, 30 mg/Kg. Excellent results were obtained in the twin girls not in the index boy. The clinical expression of this illness is variable, and an elevation of aminotransferase must call attention to this possibility. Early diagnostic and treatment could avoid the development of hepatic damage and cirrhosis.