Microporous activated carbon pellets have been prepared from date stone without the use of a binder. These pellets were tested as electrodes for capacitive deionization. The activation process involved two steps. First, a pyrolysis of the date stone was conducted to a temperature of 1000 degrees C under nitrogen flow. Then, the obtained carbon monoliths were physically activated at 900 C under CO2 flow. Elemental analysis, BET, SEM, mercury porosimetry, conductivity measurement and electrochemical performance testing carried out to characterize the structure and the properties of activated carbon pellets. The activated carbon exhibited predominant micro porosity with a specific surface area of 896 m(2) g(-1) which leads to the highest specific capacitance 270.90 F/g. The performance of activated carbon electrode at 900 degrees C in capacitive deionization (CDI) test was also examined.