this research studied the adsorption and the desorption of the herbicide 2,4-dichlorofenoxyacetic acid (2,4-d) in soil from urbano santos - ma. the region has eucalyptus crops, and they will be used for attainment of cellulose. herbicides, namely 2,4-d, are used for clean the fields before the plantation and in the firsts 12 months. the freundlich isotherm was used as model for this study, and the 2,4-d concentration was determined through high performance liquid chromatography (hplc). this determination was studied by recoveries assays. the results suggest the 2,4-d to show bigger adsorption at organic mater of studied soil that others kinds of the soils. this can results in lower tendency of leaching and degradation, but the herbicide shows high potential of leaching when compared with others pesticides.