During the last 20 years ITIL (IT Infrastructure Library) has been evolving with the latest version published in 2007. Incident Management and Problem Management are two main activities of ITIL service operation framework which handles incidents and their root causes respectively. Service Desk systems are software tools that help IT organizations in handling incidents and problems. On the other hand since Knowledge Management emerged, many corporates adopted Knowledge Management. By adding a Knowledge Management structure to the ITIL framework in 2007 the path of utilization Knowledge Management in Service Desk system is smoothed, however, the number of Service Desk systems that have adopted a Knowledge Management structure is few and the adoption is not practical in many cases. In this paper we try to address this issue and focus on Knowledge Management structure utilization in Service Desk systems by integrating Case-based Reasoning and Service Desk structure.