Activated carbon (AC) of high methane sorption capacity was fabricated from corncob which is a cheap and abundant agricultural waste. Experimental parameters such as the particle size of ground corncob, KOH/char weight ratio, temperature and time for AC activation were optimized for best sorption capacity of methane. The physical properties and amorphous chaotic structure of AC were characterized by BET, XRD and HRTEM investigations. The AC derived from corncob showed specific surface area of 3227 m2/g, pore volume of 1.829 cm3/g, and narrow pore size distribution. The results of methane sorption in the presence of water (water/carbon ratio = 1.4) revealed methane storage could be as high as 43.7 wt% methane per unit mass of dry AC at 2 °C and at a pressure less than 5.7 MPa, significantly higher than these (32 and 41.2wt%) observed on the coconut-derived AC (1800 m2/g) and ordered mesoporous carbon (1100-1200 m2/g).