Biosorption experiments were carried out in batch process for the removal of malachite green from its aqueous solution using pithophora sp, a fresh water algae as an adsorbent. The sorption capacity was found to be 45.017 mg/g at 30°C for an optimum solution pH of 3.25. The dye cations were found to get adsorbed onto pithophora sp due to strong electrostatic force of attraction. Negative value of free energy change indicates the spontaneous nature of biosorption. © 2012 Elsevier B.V., All rights reserved.