This article is about a research project focused on the development of a common knowledge base for social work education in the Netherlands. Recent substantial changes in society and social policy were the reason for a reconsideration of the educational content of social work education. A great urgency was established with regard to the adaptation of the study programs, including a higher level of knowledge. The aim of the project was to provide a knowledge base that creates a bridge between theory and practice and between social work practice and the societal context. The project started with an exploration of literature focusing on the significance of knowledge for professional practice and on existing classifications of the knowledge base in social work education. Subsequently a design-based empirical study was carried out using the Delphi-method. Experts agreed about the definition of the knowledge base and about the design requirements: practice-based, science-based, usable and sustainable. After an exploration of the content, a model was developed consisting of seven building blocks (BBs). The common knowledge base has been established by the Dutch Council of Schools of Social Work and is being used as the basis for the body of knowledge in all curricula of social work education in the Netherlands.