In the last few years, extensive research has been dedicated to development of a novel osmotic membrane bioreactor (OMBR), which combines high-retention osmotic separation and biological reactions in a single vessel. Although promising results have been reported in the literature, some challenges associated with applications of OMBR remain unresolved at the present stage of development, including lack of a high performance forward osmosis (FO) membrane, identification of an ideal draw solute and effect of salt accumulation on biological activity. Therefore, this paper attempts to provide a comprehensive review of state of the art of OMBR for water and wastewater reclamation. (C) 2012 Elsevier Ltd. All rights reserved.