Ulsan is one of the most industrialized cities in Korea, thus it has many sources of pollutants. However, the Taehwa river located in this city has been rarely researched about trace organic pollutants. Therefore, we collected water samples at 18 sites from the Taehwa river in February 2011 and analyzed 15 US-EPA priority polycyclic aromatic hydrocarbons (PAHs). The concentrations of 15 PAHs ranged from 17.0 to 250 ng/L in dissolved phase and from 81.3 to 195 ng/L in suspended particulate phase, respectively. These levels were much lower than those in China, but similar to or higher than those in Korea. Contrary to our expectation, the levels of PAHs at upstream sites were higher than those at mid and downstream sites. Furthermore, the fractions of heavier compounds with 5 and 6 rings at the upstream sites were much higher than those at other sites. These results suggest that agricultural activities (e.g., open burning) and relatively low water levels might affect the levels and patterns of PAHs at the upstream sites. On the other hands, the levels of PAHs at the downstream sites, which are located at the vicinity of industrial complexes, were comparable with those at the midstream sites. This result was probably due to dilution in the downstream and non-point sources in the midstream. Now, we continue collecting water samples at the same sites in this study to observe the seasonal variations of the levels and patterns of PAHs and to investigate the influence of potential sources surrounding the Taehwa river.