Modern day crises demand organizations to collaborate and adapt to new roles, functions and structures. In such situations, lack of collaborative behaviour and openness between organizations can result in reduced adaptive ability. Therefore, it is important to facilitate collaboration between organizations. We have studied the extent to which crisis managers are prepared to work with personnel and resources from organizations other than their own when responding to crises. An experiment was designed with four different organizations in Sweden, which involved decision making concerning whether the participants systematically favoured their own organization over others. Findings indicate that increasing familiarity and expectation of future cooperation with other organizations increased the likelihood that decision makers would be prepared to work with other organizations in joint crisis management.