A process-centric approach helps an organization to improve the way it works with. It allows scalability and provides a way to capitalize knowledge on best practices. It also makes better use of resources and helps to understand trends. PMBOK is a project management methodology, while CMMI is a model for process improvement. In this paper, we conduct a study on PMBOK and CMMI frameworks to show that they can be converged and complementary. We expect this paper research will be useful for organizations to deploy a new approach of continuous process improvement based on pooling CMMI and PMBOK.