The actors in charge of an emergency response are confronted with severe difficulties in coordination and decision making, especially in major accidents. To facilitate coordination, various decision support systems (DSS) integrated in communication systems have been developed. However, many DSS in the rescue service organizations are afflicted with under-use and other usability problems. Drawing on both a literature review and an analysis of recently obtained survey data from rescue personnel concerning usability of common communication system in Swedish emergency organizations, this paper addresses the issue of usability of DSS. It is concluded that the impetus for developing DSS in many cases has been the technological possibilities per se, not taking the decision makers task structure and contextual factors into account. It is argued that priority should be given to functions that provide a visual overview of the event and facilitate storing of the series of decisions made during the response