Alpha 1-antitrypsin deficiency is an inherited metabolic disorder that predisposes the affected individual to chronic pulmonary disease, in addition to chronic liver disease, cirrhosis, and hepatocellular carcinoma. Just over one-third of genetically susceptible adult patients with the most severe phenotype, PiZZ, develop clinically significant liver injury. The clinical presentation of liver disease is variable, and the genetic and environmental factors that predispose some individuals to liver disease while sparing others are unknown. The mechanisms of liver and lung disease are distinct and unique. This article reviews the liver disease associated with alpha 1-antitrypsin deficiency, emphasizing the genetic defect, molecular pathogenesis, natural history, and promising therapies.