Oil palm kernel shell, which is the by-product of the palm oil industries, can be used as the raw material for the production of activated carbon. Activated carbon has been widely used as an adsorbent in waste treatment and purification processes due to its high porosity and large surface area. Among the factors that affect the porosity of an activated carbon are the precursor material, the carbonization and the activation operating parameters. Carbonization process leaves an imprint effect on the porosity of activated carbon. A study has been conducted to assess the effects of carbonization time on the structural development of chars and activated carbons from oil palm shells. Samples, prepared in a fixed bed reactor, were carbonized under a continuous flow of oxygen-free nitrogen at 900oC at different duration of times ranging from 1 to 12 hours. The chars were further activated using steam as the activating agent in a fixed-bed reactor at 830oC. The activation time was varied from 40 to 210 minutes to produce activated carbons with different degree of burn-offs. Detailed properties of the products obtained are reported in this book.