Poly ethylene glycol (PEG)-poly acrylic acid (PAA) based aqueous two-phase system (ATPS) was selected as a practical model to recover glycosaminoglycans (GAGS) from tannery wastewater. The influence of PEG molecular weight, tie line length (TLL), pH, temperature and NaCl concentration on the partition coefficient of glycosaminoglycans from tannery wastewater was studied. Partition coefficient of glycosaminoglycan decreases on increase of PEG molecular weight. NaCl concentration and temperature, whereas it increases with increase of pH. In the PEG-rich phase, increased partitioning of GAGs was observed with increase in TLL The partitioning of GAGs was better in PEG 4000 at pH 8.0, 20 degrees C with a yield of 91.50%. This study demonstrates the potential application of ATPS processes for the recovery of GAGs from complex biological suspensions. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.