Belgium faces long-lasting challenges regarding the labour market activation of vulnerable groups, which includes people with health conditions and disabled people. As part of the “Negotiating return to work in the age of demographic change through industrial relations (REWIR)” project, this working paper explores the role played by industrial relations actors in Belgium in designing and implementing return to work policies at national and company level in order to support the labour market reintegration of individuals suffering from chronic diseases. The project website: https://www.celsi.sk/en/