National hospital admission frequencies were analysed for asthma (ICD-9 code 493), acute bronchi(oli)tis (ICD-code 466), pneumonia and influenza (ICD-code 480-487), and chronic obstructive pulmonary disease (ICD-code 490-492 and 496) for 1980-1989 by sex and according to age (0-4 years, 5-9 years, and 10-14 years). Rates per million of the childhood population per year were calculated and time trend analyses performed by least squares regression. In the age group 0-4 years the admission rates for the respiratory diseases were highest and a general tendency towards increasing rates was present, and significant trends were found for asthma and acute bronchi(oli)tis. In the age groups 5-9 years and 10-14 years the admissions rates were considerably lower and fluctuated with no trends to point to except for a significant increasing trend for acute bronchitis in girls aged 5-9 years and a significant decreasing trend for asthma in boys aged 10-14 years. From the presented data it can be concluded that in childhood the health issue with respect to the respiratory diseases concerns the very young in particular.