Abstract
In a prospective study a population of 32,281 newborn infants in Sweden was screened for signs of respiratory disease. All affected infants (2.9%) were investigated systematically and classified. Incidence and case fatality rates were calculated and related to gestational age, birth weight, sex and postnatal asphyxia, all of which strongly influenced 1 or both rates. The diagnostic system used was found suitable for future epidemiological research.