Laboratory experiments were carried out to investigate the adsorption behaviour of dibutyl phthalate (DBP) on marine sediments collected from five different sites in Victoria Harbour, Hong Kong. DBP adsorption can be well described by the Langmuir isotherm. The maximum DBP adsorption capacity (Q max ) of the marine sediments ranges from 53 to 79mgg −1 , which has a positive correlation with their organic content. Around 90% of the organic can be removed from the sediments with treatment by H 2 O 2 oxidation, and the Q max then decreases to a range between 13 and 22mgg −1 . The black carbon content of the sediments has a much greater DBP adsorption capacity than does the natural organic matter of the sediments. The amount of DBP adsorbed on the sediments increases as the salinity of the marine water increases.