The end of the Cold War appears to have ushered in forms of armed conflict that are less state versus state wars and more internal wars and conflicts, or what some writers refer to as "new", "post-modern" or "residue" warfare. The change in contemporary warfare has made it necessary to find new ways to deal with the new issues qand challenges that these types of warfare produce. UN Secretary General Boutros-Ghalis´1992 report, Agenda for Peace, introduced the concept of peace-building as a way for the United Nations (UN) to improve on its capacity in conflict prevention. The Brahimi Report of 2000, followed with the concept of integrated missions and recommended that UN peace missions focus on coordination and coherence between the military and civilian/humanitarian organisations in order to have a greater impact on the peace process as well as having clarity and the effective use of resources. Today´s peace operations have tended to comprise of both - peace -building and integrated mission - and the United Nations Mission in Sierra leone (UNAMSIL) was one such mission. This study provides an overview and analysis of the peace-building activities carried out through Integrated Mission, UNAMSIL, and how these activities contributed to the peace-buildning process within Sierra Leone, between 1999 and 2002. It looks at how the Integrated Mission grappled with providing security and peacekeeping, while simultaneously embarking on long-term peace-building activities. The publication was written to support the FOI research project "Command and Control in Multifunctional Environments", which is funded by the R&D programme of the Swedish Armed Forces.