Alpha1-antitrypsin (AAT) deficiency is a genetic disease that is widely known in Europe as a disease of white individuals, who, along with their descendants in other parts of the world, are at the highest risk for liver and/or lung disease. There is a limited database of individuals affected by this disease worldwide. It has been estimated, for example, that there are 70,000 to 100,00 individuals affected in the United States, with comparable numbers in Europe. Genetic epidemiologic studies in the peer-reviewed literature have been used in an exploratory study to estimate the number of carriers and the number of those individuals who are homozygous or heterozygous for the two most common defective alleles for AAT deficiency in 58 individual countries. The total country database of 373 control cohorts has been combined to estimate the numbers of carriers and deficiency allele combinations for PiS and PiZ in 11 geographic regions and worldwide. The study was designed to be illustrative rather than comprehensive, and more detailed publication of the enormous database developed in this exploratory study is planned. The database presented indicates that in a total population of 4.4 billion in the countries surveyed worldwide, there are at least 116 million carriers (PiMS and PiMZ) and 3.4 million deficiency allele combinations (PiSS, PiSZ, and PiZZ). Furthermore, this database demonstrates that AAT deficiency is found in various populations of African blacks, Arabs and Jews in the Middle East, whites in Australia/New Zealand, Europe, and North America, central Asians, far east Asians, and southeast Asians. These data demonstrate that AAT deficiency is not just a disease of whites in Europe, but that it affects individuals in all racial subgroups worldwide. In addition, AAT deficiency may be one of the most common serious hereditary disorders in the world.