With the purpose of trying to analyse the difference in hospital admission of children in urban and rural districts, the sum of discharges of selected diagnoses was withdrawn from the Danish patient register for the year 1988. The data included children aged 0-14 living in Copenhagen city and the counties of Copenhagen, Vestsjaelland and Sønderjylland. A large group of diagnoses for respiratory tract infections and a variety of other diagnoses were chosen. The admission rate for the age group 0-2 years with upper and lower respiratory tract infections plus those with fever without an infectious focus is found to account for one third of the difference in admission rate between the urban and rural areas in this age group. For children aged 3-14 there is only a minor difference concerning the infectious diseases. All age groups of children in the capital area have higher admission rates for cerebral concussion than children in the two rural counties. As for the remainder of the selected diagnoses, there is a tendency, to slightly more admissions in the county of Copenhagen and particularly in Copenhagen city.