Severe alpha-l-antitrypsin deficiency was first described by Laurell and Eriksson in Sweden fifteen years ago and has become clearly associated with an early onset obstructive lung disease in childhood or young adult life and/or serious liver disease in infancy, childhood or adult life. Sensitive, inexpensive and specific screening methods are available for detection of Pi Z or Pi MZ alpha-a-antitrypsin deficiency in serum. Several large community surveys have been performed, in an attempt to correlate the Pi MZ phenotype with a history or clinical findings of pulmonary disease. A few large population studies of working individuals have been published, in which full pulmonary histories, lung function analysis and alpha-l-antitrypsin Pi typing have been done. There is no specific treatment for alpha-l-antitrypsin deficiency at the current time, although there is promise that replacement of this serum protein or provision of a substitute protease inhibitor to deficient individuals will be available in the relatively near future.