Chitosan-silica hybrid adsorbent has been successfully synthesized by extracting the silica of Timor Island-East Nusa Tenggara (NTT) in order to study its application to Cu 2+ adsorption in water samples. This work consists of several steps which include silica extraction from Takari sand of East Nusa Tenggara, preparation of chitosan-silica hybrid, FTIR and SEM characterization, and adsorption of Cu 2+ . The successful extraction of silica was indicated by the existence of-OH, siloxane (Si-O-Si), Si-O in silanol (Si-OH) peaks at 3433.29 cm -1 ,468.70 cm -1 , and 958.62 cm -1 , respectively. The formation of chitosan-silica hybrid adsorbent was denoted by a peak shift of-OH in silica to3404.36 cm -1 , N-H stretching vibration at 1544.98 cm -1 due to an interaction between O-H in silica with N-H in chitosan, and amine (primary-NH) bending vibration at1639.49 cm -1 . The surface morphology of silica changed when it was modified with chitosan from homogeneous granule to a cluster (larger particle sizes). Optimum adsorption conditions toward Cu 2+ were achieved at pH 8 and contact time of 50 min, resulting in excellence adsorption efficiency of 99.3%. Adsorption of Cu 2+ fitted Langmuir isotherm with the adsorption capacity of 27 mg/g.