Community-acquired pneumonia (CAP) is of predominant interest in analysing the burden of airway diseases. No population-based incidence data for children in Germany exist. In retrospective cohort studies from 1999 to 2001, parents of an entire age-class (28,000-30,000) of 5-to 7-year-old children at school entry medical examination (S1) in a complete federal state (Schleswig-Holstein, population 2.77 million) were interviewed by the Children and Adolescent Service of the Public Health Service. CAP was defined as pneumonia diagnosed by a physician at the time it occurred. The proportion of children investigated (participation rate) was 82.0-86.1%. The CAP-positive rate was 6.7-7.4%, 6.9-8.2% of whom had recurrent CAP. The mean age at first CAP was 36.4-39.4 months (median 42 months). This resulted in a population-based incidence for the age groups 0-1 year and 0-5 years (under 5) of 1,664-1,932 and 1,369-1,690 per 100,000, respectively; 93.7-95.9% received antibiotics. For each percent of CAP, 458 days (1999), 312 days (2000) and 319 days (2001) of at least one parent's work were lost, respectively. Conclusions: Despite a relatively weak case definition, the population-based incidence of CAP before school entry was the same as recently reported form California and about 30-50% of that reported 20 to 40 years ago in the USA and Finland.Keywords Cohort AE Pneumonia AE School entry AE Incidence AE Public health serviceAbbreviations ARI acute respiratory tract infection AE CAP community-acquired pneumonia AE CAS children and adolescent service AE LRI lower respiratory tract infections AE PHO public health office (Gesundheitsamt) Subjects and methodsIn three retrospective cohort studies from 1999 to 2001, parents of children aged 5-7 years were interviewed by the Children and Eur J Pediatr (2003) 162: 309-316