Leather processing involves discharge of high-value soluble globular proteins in the wastewater. The recovery of value-added products from the wastewaters is gaining more importance in the context of recovery of wealth from waste. The recovery of these globular proteins from tannery wastewater was selected as a practical model system to study the implementation of polyethylene glycol (PEG)-sulfate aqueous two-phase systems (ATPS). The partition coefficient of bovine serum albumin is comparable to that of soluble proteins from tannery wastewaters. The influence of concentration of polymer, salt, pH and temperature on the partitioning of soluble proteins from tannery wastewaters has been studied. The PEG6000 + sodium sulfate + water system provide better partitioning of these soluble proteins as compared to PEG6000 + ammonium sulfate system. The maximum protein recovery yield for PEG6000 + sodium sulfate + water system at 20 degrees C is 92.75%. The influence of temperature indicates the recovery of proteins from tannery wastewater to be better at lower temperature. The findings of these studies raise the potential application of ATPS processes for protein recovery from complex biological systems. (c) 2006 Society of Chemical Industry.