Persistent organic pollutants (POPs), which include polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), are widely distributed in the environment. Some investigations have demonstrated that these pollutants will cause potential impacts such as carcinogenic and mutagenic for human health. In this study, we analyzed the concentrations and distributions of PAHs and PCBs in sediments of the Er-ren River, as well as the relations with total organic carbon (TOC) and particle sizes. Several molecular ratios were utilized to distinguish the major sources in this study. Results showed that PAH and PCB concentrations in Er-ren River ranged from 12.1 to 1460 and 0.45-591 (ng/g dw), respectively. The maximum concentrations of PAHs and PCBs were mostly found in sediments from Sanyegong River. In comparison with other studies all over the world, the concentrations of PAHs in this study were between low and mid-low levels. PCB concentrations in sediments of the Er-ren River were lower than those reported from previous studies. PAH and PCB concentrations showed no significant correlation between TOC and particle size. Petrogenic and petroleum combustion origin were the main sources of PAHs in sediments of Er-ren River In addition, perylene was the most dominant compound in Er-ren River, suggesting that it could be a useful indicator to differentiate various PAH sources in sediments. The results of hierarchical cluster analysis (HCA) and principal components analysis (PCA) indicated that PAH groups were clustered based on the loading of perylene, while PCB groups were clustered by the compositional homologues of PCBs. Comparing with sediments quality guidelines (SQGs), the PAH concentrations in all the sampling sites were below ERL value, suggesting that few adverse ecological effects would arise from the PAHs. However, the PCB concentrations in 14 sampling sites ranged between TEL and PEL values, indicating that adverse effects could arise for benthic organisms. The £UESBTUFCV of PAHs and the toxic equivalents (TEQ) of PCBs were both lower than quality values reported, suggesting that adverse ecological effects might be not expected.