A legal and institutional framework has been established in the EU to ensure a high-quality recycling and disposal of waste oil that is compatible with the best public interest. The end-of-life treatment of waste oils is regulated by the Waste Framework Directive 2008/98/EC (EU 2008). To evaluate the efficacy of the legal framework and its implementation in the EU member states, the end-of-life situation of waste oils needs to be investigated periodically. In this study, waste oil return rates per lubricant type were investigated for Belgium. The methological approach included a broad literature review, surveys among practitioners, various technical discussions and expert meetings as well as additional expert consultations to close data gaps.