Bagasse fly ash was converted into an inexpensive adsorbent and utilized for the removal of beta-naphthalenesulfonic acid in dilute solution. The effect of pH, temperature, adsorbent concentration, and co-existed acids on the removal of beta-naphthalenesulfonic acid was examined. The adsorption data have been correlated with both Langmuir and Freundlich adsorption models. Thermodynamic parameters obtained indicate the-feasibility of the process, and kinetic studies provided the necessary mechanistic information of the removal process.