Ammonium nitrogen (NH4 + -N), is one of the most common chemicals found in water ecosystems. Removal of ammonium, which is toxic to living things is a requirement and also important in terms of evaluating the regaining as a renewable energy source. In this study, membrane films were prepared from a natural biopolymer chitosan by solution casting method to remove ammonium from water. It was crosslinked by epichlorohydrine for stability and usage of that films as an adsorbent was investigated. The suitability of data obtained to adsorption isotherms and adsorption kinetic models were investigated. The maximum adsorption capacity was reached as 15.6 mg NH4+N/g adsorbent for 100 mg solution concentration at 25 degrees C by using 0.25 g adsorbent dosage. The experimental equilibrium data were matched with the Langmuir and Freundlich isotherm models. Adsorption process succeeded the pseudo-second- order kinetic model.