Inherited alpha-1 antitrypsin deficiency is listed among the three most common genetic disorders in Caucasians. It considerably increases the risk of progressive obstructive lung diseases, mostly chronic obstructive pulmonary disease, as well as chronic liver disorders, hepatitis, cirrhosis, and cancer. It is estimated that more than 5.5% of the Polish population carries one of the most common deficiency phenotypes, which might be relatively easily detected due to low alpha-1 antitrypsin serum concentration. However, as well as being quantitative, alpha-1 antitrypsin deficiency might also be qualitative. These dysfunctional alpha-1 antitrypsin variants are characterized by scarce antiproteolytic activity and quite often by fully effective protein production resulting in normal serum levels. Consequently, dysfunctional variant identification is possible only by means of pheno- or genotyping. This review presents clinically useful characteristics of main genetic alpha-1 antitrypsin variants.