During the growth of a competitive global enviroment, there is considerable pressure on most organisations to make their operational, tactical, and strategic process more efficient and effective. An information system (IS) is a group of components which can increase the competitiveness and gain better information for decision making.Consequently, many organisations decide to implement IS in order to improve the effectiveness and efficiency of their organisations. However, a lack of awareness of numerous and varied challenging issues surrounding the implemenation process could be problematic for the whole process. Furthermore, the problem of a lack of key success issues seems to be a serious obstacle for the management information system (MIS) implementation process. Additionally, MIS implementation has effects on an organisation and these effects are related to the consequences of the business processes. Consequently, this issue is critical and crucial for an organisation to consider when they implement a new MIS. The main purpose of this thesis is to present the MIS implementation challenges or problems together with identifying the key issues to successfully achieve implementation. Such challenges and success factors are conducted based on a research framework. In addition, this research accesses descriptions of implementation effects and consequences which impact the organisation and its processes.This thesis has been conducted by studying the theory divided into three parts including:general background literature of information systems, implementation aspects, and organisational impacts literature. The methods that were used to successfullly accomplish this study were a case study of Fenix System, collecting data by personal interviews with respondents who were involved in Fenix along with internal documents.The analysis of the research framework and empirical findings has contributed to adescription of the main challenges and key success issues regarding MIS implementation, together with an identification of important effects and consequences when implementing MIS. This thesis’s main results show that MIS implementation issurrounded with challenges which mainly concern management, adminsitration, and people issues involved in MIS implementation process. Additionally, it was concluded that the key issues which the MIS implementation project should be presented with primarily focused on the project team and their team work. The last main finding is concentrated on effects and consequences and it found out that MIS implementation mainly affects business process which lead to change, for instance jobs, routines, and so forth.