The aim of this thesis was to understand the validation of vocational knowledge prior to entry into vocational teacher education in Sweden. From this aim the following research questions were developed: What ideas about the organisation of validation stand out in the policy and practice of validation? What conceptions and understandings of vocational knowledge is the organisation of validation built on and what do they entail? Who has the agency to describe and decide upon vocational knowledge in the policy and practice of validation? What institutional arrangements appear in the practice of validation? To conduct the studies a multimethod approach was adopted, combining policy analysis and interviews. For theoretical support, new institutional theories were used and also theories of knowledge. The results revealed that validation have transformed vocational knowledge to fit a frame similar to formal education. It appears as if validation is more of a social and economic project than one of accounting for vocational knowledge and pride. Cultural/cognitive matters that are taken for granted when considering vocational knowledge differ quite significantly between agents involved in validation. Validation of vocational knowledge exhibits a conceptual confusion having different conceptions of knowledge simultaneously at play. In the complexity of ideas of how to organise validation and different knowledge conceptions, institutional arrangements appear to be based on a sense of belonging, either to academia or to the trade. The agency of those with vocational knowledge is limited in several ways within validation.