In the Federal State of Baden-Wuerttemberg, Germany, an environmental health surveillance system has been established focusing on children aged 10 years. Four study regions (two larger cities, one small city, and one rural area) were designated in order to get information about the body burden of persistent chemicals (toxic metals and chlorinated compounds) in children and about lung function, frequency of respiratory diseases, and allergies. From 1992/1993 to 2002/2003, seven cross-sectional investigations were carried out, and more than 10,000 children took part in the study. DDE, HCB, PCB-138, PCB-153 and PCB-180 were measured in individual blood samples of about 400 children per year, whereas PCDD/PCDF and coplanar PCBs were determined in pooled blood samples. From 1993 to 2003, blood concentrations of these compounds decreased 2 to 4-fold. Concerning regional differences, slightly lower concentrations of DDE, PCBs and PCDD/PCDF could be seen in children from the municipal population of Mannheim compared to other regions. Breast feeding was associated with considerably higher concentrations of PCBs and most other chlorinated compounds. Static and dynamic lung function parameters showed no differences between the investigated areas. For prevalences of respiratory diseases and allergies, no time trend was observed except for pertussis, which showed a decrease in 2002/2003 probably due to an increase of vaccination rates. In addition, the prevalence of atopic sensitization against aero allergenes remained unchanged at about 35% during the observation period. In conclusion, this environmental health survey delivers objective data about spatial and temporal trends and provides information about possible sources of children's exposure to toxic compounds in the environment. Adaptations of the survey to new problems are discussed.