The development process of a Decision Support System starts with the Problem Analysis. The goal of this phase is to assess the needs of the end-user(s) and to obtain a crisp diagnosis of the problems, the type and extent of the policy field within which they are posed, and the actors involved. This is a process of divergence that begins with exploring the needs and possibilities. The process ends with making choices that get further deepening and elaboration in the remainder of the development process. It is not possible, nor is it useful or advisable, to elicit all the elements that matter in the beginning of the development process, rather an iterative approach is needed. In the past years RIKS has carried out many a problem analysis in the context of a DSS development project. To structure the work we have developed a checklist with questions covering the following six categories: Reason(s) for building a DSS: goals, criteria and expectations; Characteristics of the system concerned: region, city, coastal zone or river basin; Cultural aspects of the political arena; Institutional context; Policy problems requiring solutions; (end-)Users of the DSS: required functionality, use, and usability. Answers to the questions are sought in an iterative process involving interviews with end-users and domain experts, literature research, and investigation of skills and behaviour of the end-users. We try to optimise the exchanges between the end-users on the one hand and the development team on the other hand. The former are the problem owners, but rarely know exactly what it is that they want, nor what they can expect from a DSS. The latter are experts in DSS development, but do not know the precise context of the problem, the competence and working methods of the end-users, nor the internals of their organisation. Besides answering the abovementioned questions informing the potential end-users of the capabilities of the Decision Support System and gaining support for using the kind of system in their decision-making are of great importance during this phase. For more information about the possibilities of RIKS for carrying out a problem analysis, please contact Hedwig van Delden.