One hundred and twenty nine workers in the cork industry, 69 rural workers, 66 carpet makers, 58 workers in a granite quarry and 51 workers in a rice husking factory were studied from an epidemiologic point of view. All were submitted to a standard questionnaire planned to detect respiratory disease due to inhalatory causes. They were submitted to a clinical examination, summary ventilatory function tests, a 70 mm microradiograph, and blood was taken to determine alfa-one antitrypsin and its phenotypes and, in the cork industry workers and rice husking workers, the level of IgA, IgG and IgM. The results are presented and an attempt is made to correlate the various parameters among themselves, and namely alfa-one AT phenotypes with the existence of respiratory pathology. Finally the results are discussed.