A Dissertation Submitted in Partial Fulfilment of the Requirements for the Award of the Degree of Masters of Business Administration-Corporate Management (MBA-CM) of Mzumbe University.How to be successful in this global era has different implications to what it was destined in the past. Project processes have moved from project management to portfolio management which needs strategic decision making in order to optimise resources and overall returns as well as to balance risks posed by projects. Traditionally it was assumed that project stakeholders were in one location and had similar cultural backgrounds. Under the status quo, this belief has become worthless; project stakeholders are culturally more diverse and the advancement in ICT has made it easier for projects to be implemented from anywhere in the world. As a consequence, other critical success factors have started to impact the traditional benchmarks. The aim of this study is to find out the reasons why multicultural projects delay or fail and consequently to convey critical success factors for multicultural project portfolio management at MIC-Tanzania. The research was carried out by means of questionnaires and interviews where project portfolio managers as well as stakeholders from “factory” were invited to share their experiences of the same. Literatures acknowledge the importance of project portfolio management and why at MIC-Tanzania some projects fail or delay yet address the impact of cultural diversity in project portfolio management. Based on the research findings, the following critical success factors have been identified: project stakeholders’ competency, commitment, positive attitude, proper time management, quick adaptation skills, cultural diversity training prior to departure to international assignments as well as exhaustive knowledge of industry culture, organisational culture and host culture. There should also be organisation’s good communication policy, well-articulated dispute resolution mechanisms, precisely planned supply logistics, well-defined project roles and responsibilities as well as reliable Information and Communication Technology infrastructure.