Until the 1970s, polychlorinated biphenyls (PCB) were used as industrial chemicals for diverse commercial applications, leading to a ubiquitous contamination of nature and man. In the 1980s, PCBs were prohibited by law in many industrialized countries. Hence, in recent years a steady decline in PCB levels has been seen. Here we report on PCB plasma levels in children and adults in Germany in 1998. 130 children/youth (0 to <18 y) and 494 adults (18 to 65 y) living in an urban environment participated in this study. Occupational exposure to PCBs was excluded by questionnaire. Gas chromatography/electron capture detection was used to analyze blood plasma samples. In all blood specimens, PCB congeners 28, 52, and 101 were below the limit of quantification (<0.1 microg/L) and only the congeners 138, 153, and 180 were detected. The 95th percentiles in the age groups 0 to <6 y, 6 to <12 y, 12 to <18 y, 18 to 25 y, 26 to 35 y, 36 to 45 y, 46 to 55 y, and >55 y were as follows: PCB 138: 1.02; 1.05; 0.61; 1.01; 1.22; 1.44; 2.23; 2.94 microg/L plasma; PCB 153: 1.47; 1.23; 0.59; 1.26; 1.53; 2.11; 3.27; 3.98 microg/l plasma; PCB 180: 0.88; 1.23; 0.39; 0.88; 1.16; 1.71; 2.16; 3.31 microg/L. In adults, plasma levels of PCBs increased with age. In comparison with published reference values on internal PCB exposure in the population in Germany, based on data obtained in 1991/4 and 1994/5, the steady decline in PCB levels reflects the falling external and internal PCB exposure after the ban on PCB. For the first time, current PCB exposure during childhood and adolescence in Germany is provided here. In childhood, internal PCB exposure declined with age, especially in children who had been breastfed. An impact of breastfeeding on internal PCB exposure was found in age groups up to 12 years old.