Most of the existing studies on health effects from expo sure to pollutants are limited in their scope. In an attempt at a more holistic approach the Government of the Czech Republic implemented a decree entitled 'A System of Monitoring Environmental Impacts on Health of the Pop ulation of the Czech Republic'. A monitoring system comprising six parts was set up to provide data neces sary for a national policy for health and protection of the environment. This paper describes work carried out on a cohort of kindergarten children in Brno, Hradec Králové, Ostrava and Plzeń under the subsystem of the decree: 'health consequences and risks related to air pollution'. It was found that 20% of the children monitored had long- term respiratory complaints, which, potentially, could be associated with the quality of indoor air. There were no differences between the towns, sex or age of the children related to these health problems. The study looked at various domiciliary factors including type and structure of housing, heating system, use of gas cookers, new fur niture and carpets, presence of mould, pet animals and smoking indoors. Surprisingly, in families with sick chil dren, there were fewer pets and also fewer smokers.