In order to investigate temporal and spatial distribution of organic pollutants in the Saemangeum Bay, organophosphorus pesticides (10), alkylphenols (7), chlorophenols (2), bisphenol A were analyzed from surface seawater and surface sediment samples taken in 2002-2003. Most of the analytes were not detected in all stations and matrix except nonylphenol and IBP. Concentrations of nonylphenol in surface seawater and surface sediment were ranged from ND to 298.0 ng/l and from ND to 11.8 ng/g dry wt respectively. Concentrations of IBP in surface seawater were ranged from ND to 1841 ng/l. Organophosphorus pesticides were not detected in surface sediment. The high levels of nonylphenol and IBP were found in the estuary areas of Mankyoung and Dongjin River. The levels of nonylphenol and IBP in water were changed by season, the high levels of nonylphenol and IBP were found in summer season (Jul. and Aug.). It was fount from sequence monitoring study and correlations between concentrations of target compounds and contents of salinity in seawater, that physical mixing and diffusion factor by the seawater is a major parameter effecting on spatial distribution of IBP and nonylphenol in the Saemangeum environment.