The success of deploying Information Systems (IS) by organizations is dependent on the full integration of the new innovation into their existing processes (Diffusion). The failure of an IS to be fully diffused in an organization is, in most cases, not due to any inadequacy of the technological innovation, but rather due to conflict and a lack of acceptance within the organization attempting to implement the change. The analysis of organizational sub-cultures in IS research has proved to be a valuable approach to generate deeper insights regarding IS usage and success experienced by organizations. However, organizational subculture, and specifically the fragmentation sub-culture have not yet been used to investigate the diffusion process of IS in organizations. This paper tries to fill this gap by adopting Martin’s (1992) sub-culture framework to explore the process of diffusion of a Management Information System (MIS). The six stage IS implementation model by Cooper and Zmud (1990) will be applied to the research to illustrate and investigate the process of diffusion of the MIS. The research method will be an in-depth case study. It is anticipated that investigating IS diffusion from the theoretical lens of sub-culture will significantly advance our understanding of the diffusion process of IS.