The recent success of cyclosporin marketed formulation - Sandimmune Neoral® by Sandoz in Europe has invigorated the gaining interest in microemulsions as potential drug delivery systems. These thermodynamically stable, transparent (or translucent) dispersions of oil and water stabilized by an interfacial film of surfactant molecules have potential applications whenever it is necessary to mix oil and water and where a large oil-water interface is required. Thus, microemulsions have drawn considerable interest. Until now excellent reviews covering aspects of bioavailability, theories, physical properties, formulation design, physical characterization, drug release and delivery potential have been cited in literature but there is no review that discusses the intellectual (patent) aspect of these delivery systems. In order to appreciate the intellectual potential of these delivery systems, this review summarizes the patents governing various applications of these delivery systems.