Perinatal exposure to PCBs and dioxins is associated with immune changes in healthy Dutch preschool children. To examine whether such effects persist into later childhood, we here report on the immunological effects of perinatal exposure to PCBs and dioxins in 167 Dutch children at school age. A higher postnatal PCB exposure was associated with a higher prevalence of recurrent middle ear infections and a higher prenatal PCB exposure with less shortness of breath with wheeze, as assessed by parent questionnaire. Our data indicate that, at environmental levels of these man made chemicals, subtle health effects may occur.