Effective delivery in the fields of development aid and healthcare relies on knowledge and its communication. Institutions, practitioners and the end-users are examined in these two fields as key actors in the production and communication of knowledge. Similarities and differences, and strengths and weaknesses of their approaches to knowledge are compared. Knowledge is shown to be an intrinsically political process in which institutions and practitioners play a critical role in its communication. Establishing a common background is essential to communicate knowledge effectively. The World Bank’s notion that knowledge is a simple commodity should be challenged