Adsorbed natural gas has various advantages and is relatively more economical than liquefaction and compression. In our present investigation, we have prepared the carbon monolith from a phenol resin mixed with a renewable resource (such as cotton fiber) after carbonization. The compositions were optimized to determine the highest V/Vs value with methane gas and achieved a value of 140 cm(3)/cm(3) (at 35degreesC and 3.5 MPa) with carbon monolith prepared from a 75:25 mixture of phenol resin and cotton fiber. The effects of various physical properties on the methane adsorption capacity were studied in detail. The use of carbonized cotton fiber increased the methane adsorption, surface area, and pore volume. Characterization of the carbon monoliths were performed using the Brunauer-Emmett-Teller (BET) surface area, and the pore size distribution, and the morphology was examined via scanning electron microscopy (SEM).