A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at 600-800°C and chemical activation with H3PO4 at 500°C. Some carbons were treated at 400, 600°C, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around 2θ = 23 and 43°, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of H3PO4-ACs display more developed and separated peaks in the early region with maxima at 2θ = 23, 26 and 29°, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the 2θ = 43° is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions. Keywords : Activated carbon, H3PO4-activation, steam pyrolysis, graphite structure, X-ray diffraction