In this study, activated carbon was obtained from Elaeagnus angustifolia seeds and its usability in the adsorption of methylene blue (MB) and malachite green (MG) from aqueous solution was investigated. Activated carbon was synthesized by chemical activation method using H3PO4 as an activator. In the synthesis of the activated carbon, the effects of various parameters such as the rate of impregnation, duration of activation, temperature of activation and duration of activation were investigated. The characterization of the synthesized activated carbons was carried out by FTIR, SEM and BET analyses and the surface area of the produced activated carbon was determined to be 1,194 m(2) g(-1). The effects of solution initial pH, solution initial concentration and amount of activated carbon on MB and MG adsorption were investigated. The adsorption capacity was found to be higher when the pH of the solution was 8 for MB and 4 for MG. The adsorption kinetics of MB and MG were found to fit the Elovich kinetic model and pseudo-first-order kinetic model, respectively. Adsorption equilibrium data were found to be compatible with Langmuir isotherm for both dyes. According to the Langmuir isotherm, q (max) adsorption capacity was found to be 72 mg/g and 115 mg/g for MB and MG, respectively.