Preparation and characterization of activated carbons from oil palm fruit solid wastes were studied. The effects of activation conditions (CO₂ flow rate, activation temperature and retention time) on the characteristics of the activated carbons, namely density, porosity, BET surface area, pore size distribution and surface chemistry were investigated. The optimum conditions for activation were an activation temperature of 800°C and a retention time of 30 min for fibre or 50 min for shell, which gave the maximum BET surface area. Adsorption tests showed that the activated carbons from oil palm fibre and shell could be used as adsorbents for both liquid-phase and gas-phase adsorption.