Removal of Cr(VI), Cu(II) and Fe(II) from aqueous solutions has been studied using fly ash (FA) and Na-fly ash (Na-FA) as adsorbents. The process of adsorption has been established to be dependent on concentration of the metal ions, time of contact, dosage of adsorbent and on temperature. The adsorptive behaviour has been found to fit in Freundlich adsorption isotherm. Ion exchange and complexation at the surface are the major mechanisms involved in the removal of metal ions from aqueous solution. Na-fly ash is found to have better adsorption capacity than FA which is attributed to the increased content of Na ions on the surface which is readily available for exchange with metal ions. The observed results indicate that Na-FA has excellent adsorption capacity compared to FA and can be used as a potential cost-effective adsorbent for removal of heavy metal ions from industrial effluents.