This study was carried out in the Troia (Troy) National Park, a secondary bird migration corridor on the North-South axis in northwest Turkey, which was proclaimed a national park in 1996, and a world cultural heritage in 1998 by the UNESCO on account of its archeological richness. The aim of this study was to determine the residues of widely used pesticides, such as α- and β-hexachlorohexane (HCH), heptachlor, aldrin, α- and β-endosulfan, endosulfan sulphate, methoxychlor, endrin, dieldrin, fenthion, azinphos-methyl, malathion, methamidophos, diazinon, trifluralin, malathion, captan, cypermetyhrin, ethion, and mancozeb in soil as well as surface and ground water resources. Methoxychlor, α-endosulfan, β-endosulfan, α-HCH and β-HCH were detected in water samples collected from 13 sites in 4 different water resources between May and August 2003, whereas HCH, ethion, endosulfan, captan, trifluralin and mancozeb residues were found in soil samples taken according to plant patterns from 14 different sites at depths of 0-20 cm in August 2003. The residues of α-endosulfan were higher than the others, and ranged between 0.079-1.8 ppb, with an average of 0.369 ppb in May, but 0-8.3 ppb, with an average of 0.954 ppb in August. The dominant residue in soil samples was HCH (0-49 ppb), with an average of 10.07 ppb. It was concluded that the observed decrease in species and number of migratory birds in the region could be a result of the amount of pesticide residues in both water and soil resources, originating from intensive agricultural applications.