Separation of organic-organic mixtures using membrane separation techniques is being investigated extensively owing to its great importance in chemical and petrochemical industries. Pervaporation is today considered as a basic unit operation for separation of organic-organic liquid mixtures because of its efficiency in separating azeotropic and close-boiling mixtures, isomers and heat-sensitive compounds. Membranes used for separating the four major categories of organic-organic mixtures viz., polar/non-polar mixtures, aromatic/alicyclic mixtures, aromatic/aliphatic mixtures, aromatic isomers are made of materials that are organic as well as inorganic in nature. A considerable amount of background information related to the developments in the field, and the current trends of industrial pervaporation are dealt with. This review seeks to define the current scientific, and technological factors that govern the field of application of membranes for separation of organic mixtures. Potential membrane materials for further research in this area are also discussed. (C) 2004 Elsevier B.V. All rights reserved.