Several fly ash samples were collected and their physico-chemical properties were characterised using N-2 adsorption, XRD, SEM, and pH titration. These fly ash samples were applied as low-cost adsorbent; for removal of methylene blue and humic acid from aqueous solution. It is found that the adsorption has a close relationship with surface area and pore volume. Higher surface area and pore volume of fly ash will result in higher adsorption of methylene blue (MB) and humic acid (HA). The adsorption of MB and HA on various fly ash samples can reach 7 and 10 mg/g, respectively. Solution pH will also influence humic acid adsorption on fly ash and higher pH will result in lower adsorption. Ionic strength will also influence HA adsorption. (C) 2008 Elsevier Ltd. All rights reserved.