The aim of this study was to identify the social and organizational requirements for a decision support system (DSS) to be implemented in a clinical rheumatology setting, utilizing data-mining techniques. Field observations and focus group interviews were used for data collection. The decision-making was found to be situated, patient-focused, and long-term in nature. At the same time, the main part of peer-to-peer communication was informal. Patient records were involved in almost every decision. The conclusion is that the main challenges, when introducing a DSS at a rheumatology unit, are adapting the system to informal communication structures and integrating it with patient records. Considering incentive structures, understanding workflow and incorporating awareness are relevant issues when addressing these issues in future studies.