The UN-Sustainable Development Goals (SDGs) provide an attractive framework to demonstrate the essential contributions that soil science can make to transdisciplinary research. Contributions of soil science were systematically defined by considering relevant SDGs and the associated ecosystem services (ESs) for six transdisciplinary case studies in the Netherlands and Italy. Soil input consisted of available knowledge in terms of data and models in three case studies. This resulted in highly relevant research based on knowledge assembly, but is not helpful when soil scientists then demand funding for new research in order to expand the knowledge base. In three case studies not only available knowledge was used but also results from new research. An analysis of the six case studies resulted in recommendations for new soil research.