O One of the United Nations Millennium Development Goals is to reduce by half the proportion of people without sustainable access to safe drinking water and basic sanitation. Aiming at this goal, Aqua for All was asked to formulate a selection guide of simple drinking water treatment technologies for small communities in developing countries. In this research, the technologies are focused on desalination, nitrate removal, and disinfection. The technologies should be appropriate for main target users in small communities ranging from individual use, household, groups, village, to small town with maximum population of 5000 people. As for the selection guide, it is specifically aimed for more experienced users (practitioners or experts with basic knowledge of water quality and/or water treatment methods) who sought to help the main target users to solve their problems.The research was executed by collecting the needed information from several sources such as literature, interviews or consultations with experts, and internet. Laboratory testing was planned although no reliable result was attained. The main limitation of the research was time insufficiency. Nonetheless, in general, the research objectives were achieved properly.Available technologies for desalination, nitrate removal, and disinfection, are presented in the form of the comprehensive product fact sheets. To rate the appropriateness degree, as well as providing a ranking system, Multi Criteria Analysis (MCA) based on the simplified appropriate technology (AT) criteria was conducted. In total, there were 20 products i.e. six for desalination (WaterPyramid, Watercone®, Aqua Solaris, the Solar Cube, the DIY Desalination Unit, AquaCone), two for nitrate removal (Nitrate Fleck, Ameridia electro dialysis unit), and 12 for disinfection (Tulip Filter, SODIS, PUR, the Safe Water Storage, NADCC, AquaPak, boiling, Pureit, Perfector-E, Plation AquaEst, Biosand Filter, Jal-TARA SSF). More than half of the products were rated as highly appropriate, i.e. Watercone®, DIY Desalination Unit, Aqua Solaris, Tulip Filter, Biosand Filter, SODIS, SWS, Plation AquaEst, PUR, and Perfector-E. While, from the remaining products, only one was rated low, that is the electro dialysis unit. The moderately appropriate technologies are the Solar Cube, AquaCone, Nitrate Fleck, AquaPak, NADCC, boiling, Pureit, and Jal-TARA SSF.Utilizing the fact sheet as a medium for user oriented decision making process, a step by step selection guide called the Decision Support Tool (DST) was created. It takes a form of a matrix consisting of eight variables, each with its own parameters. Four of the variables are based on source water characteristics, while the rest is related to specific features of small community. The selection mechanism is based on the ‘survival of the fittest’ concept. Elimination of incompatible technology is made possible by colour categorization: green, yellow, red (the eliminating factor), and non-colour. The colours represent technology applicability of toward the parameter. The fact sheet’s DST will be the coloured version, while users will have to fill in the blank version. In this way, comparison of the two versions could be performed. The expected outcome is one or more technology alternatives. From this point onward, users are responsible in making their final selection by thoroughly consulting the fact sheets and the product ranking. For practicality, user instructions guide is provided.To improve the fact sheets, more independent testing of the products should be facilitated. Proper testing methodology is also important. For the current DST, case studies need to be conducted to assess its applicability. As in the future, another selection guide of a complete water treatment system has to be developed, as well as the possibility of creating one that can be used in unidentified situation i.e. unknown water quality. Further research on the AT criteria, particularly the cost aspect and the ranking system will also add values to the work.