Sediment samples were collected from a large reservoir and a river in northern Taiwan to investigate the occurrence and characteristics of Σ73PCNs analyzed. Results indicate that total concentrations of PCNs (Di- to Octa-CNs) measured in sediments collected in reservoir (29.2 ± 7.11 pg/g-dw) are significantly lower than that of samples collected in river (987 ± 440 pg/g-dw). The increasing trend of PCN concentration from upstream to downstream is found for the sediments collected in reservoir. PCN concentrations measured in surface sediments are relatively higher than that measured in sub-surface sediments collected in reservoir. Tetra-CNs consistently dominate in reservoir sediments, however, Penta-, Tetra- and Mono-CNs dominate in sediments collected at different sampling sites of the river investigated, suggesting that various sources contribute to PCNs collected from river. Indeed, diagnostic ratios indicate that mix-source contribute to PCNs measured in sediments collected from the reservoir and river in northern Taiwan.