SYNOPSISThe international presence in Kosovo is an example of full international administration. Its most important obligation is arguably to provide a safe and secure environment for all inhabitants, in which they can establish relations and structures for peaceful co-existence with the help of the international community. Both military and civilian agencies (KFOR and UNMIK) and many nations are involved in this project. However, history as well as research in international relations and organizational theory dictate an expectation that numerous and varied goals and preferences exist in such a scenario. This dissertation asks whether success criteria influence civil-military cooperation in the security sector of the international administration of Kosovo.An examination of KFOR and UNMIK with regards to their actual cooperation patterns in the security sector revealed conspicuous institutional differences. KFOR appears as a collection of organizational units between which there are command lines that cannot be used to issue proper orders due to national reluctance to relinquish control of their personnel. UNMIK appears more coherent institutionally, but lacks the resources and force to execute all their duties. The nature of security challenges and the resource situation have necessitated military engagement in executive policing, but KFOR and UNMIK are both reluctant due to institutional differences and preferences. KFOR and UNMIK seem to operate with partly the same success criteria – the UN mandate – and partly separate ones. The time horizon stands out as an unsorted issue, as KFOR looks to withdraw as soon as possible while UNMIK looks to stay until the situation is stable and self-sustainable. Due to these and other factors, security cooperation has to a significant degree assumed the form of ad hoc projects and solutions conducted on local and regional levels. Streamlined, uniform success criteria would probably offer enhanced economy and efficiency of joint efforts. On the other hand, it seems like the lack thereof may offer a desirable flexibility to effectuate rapid, tailored initiatives in response to sudden and unexpected challenges.