Access to microbiologically and chemically safe water is limited not only in developing countries, but also in transition Countries and even in remote areas of some developed countries. For these cases, point-of-use (POU) technologies can be promising alternatives to centralized treatment concepts. Membrane-based treatment systems have gained importance for drinking water treatment in the developed countries and can be considered as the dominant technology for new applications at present. Due to the high retention of pathogens and the possibility of downscaling (modular construction) membrane technology seems to be attractive also for application as POU system in developing and transition countries. However, no scientific publications on such systems are available and application is limited. Therefore we conducted an extensive literature and state-of-the art review to evaluate relevance, current use and the research and development needs of membrane-based POU systems in developing and transition countries. POU technologies are widely being used to produce safe and high quality drinking water in rural areas of industrialized countries, where access to centralized supply is not available, or for additional treatment of tap water. However, the cost level of POU systems applied in industrialized countries is in general not acceptable in other cases. Therefore simple low cost systems were developed and applied in developing and transition countries. In a range of case studies, described in literature, these systems show themselves as an appropriate short term solution, but often fail to provide improved access to necessary amounts of safe water. Economical growth of developing and transition countries leads to increasing public concern, affordability and requires long term sustainable solutions of the drinking water problem. Membrane-based POU/POE systems are especially attractive for application in developing and transition countries while they can provide high removal of bacteria, protozoa and viruses, have modular design and can be operated with a range of different energy sources, including mechanical and hydrodynamic energy. But, for their application in developing and transition areas, the cost level is in general not acceptable. Furthermore, the source water quality is often very low and can differ regionally as well as seasonally, and the POU/POE systems should be able to treat this kind of waters. Another critical factor in transition and especially in developing countries is the maintenance and control. Not only the level of education of the local population may be insufficient, but also structural financial means for maintenance and control may be lacking.