The concentrations of indicator polychlorinated biphenyls (PCBs No. 28, 52, 101, 138, 153 and 180) and organochlorine pesticides (HCB, p,p'-DDE and p,p'-DDT) in 121 blood serum specimens collected from non-occupationally exposed adults living in contaminated and comparison areas were determined using high-resolution gas chromatography/electron capture detection (HRGC/ECD). The sum of the serum concentrations of the three most abundant PCB congeners (No. 138, 153 and 180) found in participants (N = 81) living in industrial areas near incinerators, metallurgical and chemical plants (Krompachy, Kosice, Nemecka and Sala) was significantly higher (p < 0.001) than in participants living in villages and towns without known sources causing persistent organic pollutant (POP) contamination (N = 40). Similarly, significant differences were observed for p,p'-DDE (p < 0.0001) and p,p'-DDT (p < 0.002). However, a Mann-Whitney U test between groups showed that the difference for HCB was not statistically significant (p = 0.089). Age was positively correlated with the sum of PCBs (No. 138, 153 and 180), HCB and the sum of p,p'-DDE and p,p'-DDT (p < 0.01 for all).