α₁-Antitrypsin deficiency is an autosomal codominant condition that predisposes to emphysema and cirrhosis. The condition is common but grossly under-recognized. Identifying patients’ α₁-antitrypsin deficiency has important management implications (ie, smoking cessation, genetic and occupational counseling, and specific treatment with the infusion of pooled human plasma α₁-antitrypsin). The weight of evidence suggests that augmentation therapy slows the progression of emphysema in individuals with severe α₁-antitrypsin deficiency.