Contamination of seven heavy metals (Cu, Pb, Zn, Fe, Al, V, Ni) and PAH compounds, and physicochemical characteristics were studied in sediments of Qarasoo River, Kermanshah. The results of contamination factor (CF), pollution load index (PLI) and enrichment factor indicated severe contamination of sediments, particularly for lead, zinc and copper in some segments of the river. Also, sampling stations near the city including oil refinery and industrial town had much higher PAH concentrations than the upstream. Based on toxic equivalency factor (TEF) and comparison of PAHs concentration with effect range low (ERL) revealed inappropriate situation of Qarasoo sediments. Among the various compounds, 3-rings PAHs are dominant with maximum concentration, same as heavy metals, in oil refinery station. Based on principal component analysis (PCA) and geochemical indices effluents of Kermanshah oil refinery are the main source of contamination of low molecular weight PAHs with petrogenic origin and copper, vanadium and nickel. In addition, organic matter and pH have also shown strong correlation with this component, confirming the role of the refinery in increasing their concentration in the Qarasoo River. Other important anthropogenic sources in the Qarasoo River include urban and industrial effluent, traffic and illegal waste disposal in the river margins.