a b s t r a c tResponse to large scale emergencies is a cooperative process that requires the active and coordinated participation of a variety of functionally independent agencies operating in adjacent regions. In practice, this essential cooperation is sometimes not attained or is reduced due to poor information sharing, non fluent communication flows, and lack of coordination. We report an empirical study of IT mediated cooperation among Spanish response agencies and we describe the challenges of adoption, information sharing, com munication flows, and coordination among agencies that do not share a unity of command. We analyze three strategies aimed at supporting acceptance and surmounting political, organizational and personal distrust or skepticism: participatory design, advanced collab orative tools inducing cognitive absorption, and end user communities of practice.