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The adsorption of phosphates from aqueous solutions on a synthetic resin using a batch method was studied in the present thesis. The removal of phosphates constitutes an important issue due to the great environmental pollution to which it leads. Industries discharge big quantities of waste downgrading this way the aquatic environment. For this reason studies were carried out in order to investigate the removal of phosphate by adsorption. The epichlorohydrin – polyethylenimine resin has been used for this purpose showing good results. The study of the adsorption includes experiments concerning the determination of the most suitable parameters such as the solid to liquid ratio (S:L), the temperature, the pH of the solutions and the phosphate concentration, on the removal efficiency was examined. The adsorption of phosphate was tested in the absence and in the presence of background electrolytes (NaNO3) and competitive substances such as proteins and sugars. Kinetic studies have been performed in order to find out the rate of the process. The sorption was followed by elution of the loaded material, to test its secure disposal in the environment. For the study of experimental data, adsorption isotherms have been constructed and the data were modeled by the Langmuir and Freundlich equations as well as the linear model. The correlation coefficient, R2, was calculated to assess the quality of the fit. The quantitative determination of the phosphates was photometrically performed. It was found that the synthetic resin is an effective adsorptive for the removal of phosphates because the process is rapid, with high degree of removal and with maximum sorption capacity of 50 mg P/L.