Several organizations including Ethiopian Banking Sector have accepted the importance of a project management office, to resolve the problem of managing new initiatives in an organization. The purpose of this study is to show the role of a program management office on project sucess using the IT projects of the Bank of Abyssinia (BOA) as a case study. The research was conducted on the PMO of BOA which is located in Addis Ababa. To achieve the research objective Explanatory research design and quantitative research method is used for this study. Data collected from 31 selected respondents (PMOâ€™s staff) through a questionnaire. Analysis was done based on the PMO involvment in facilitating knowledge areas of project management, tools, and techniques (Project management tools, Project management techniques, Project Resource Management, Project communication management, Project risk management, and Project Stakeholder management). The result showed that the Pearson correlation among PMO involvement and successt sucess is moderate to strong. correlation among the perceived value of a PMO on project success is strong. Regression analysis also showed that Project communication management has the highest significant impact. There was a 73.3 % change in project success attributed to the PMO of BOA. In general, PMO has a moderate to strong effect on Project success. Although the findings are valuable, the use of only one organization limits the study, it is concluded that the PMO of BOA has very good communication management and it has a gap on implementation of standardized tools and techniques, and risk management. Therefore, it is highly recommended to use Agile project management for IT projects of BOA and improve risk management. Finally for future studies, including more banks to reduce bias and add more different structure and role of PMO.