Expectations are that 80 percent of the global population will reside in urban areas by the year 2050. As urbanisation levels increase so do ecological footprint sizes in these areas, as it is in the cities that income levels are higher, and where higher levels of disposable incomes exist. Whereas the circular economy is gaining ground as a concept for increasing sustainability by the efficient use of available materials and resources, urban areas are often recognised as attractive starting points for making the transition towards a circular economy. The paper “Circular food chains and cascading of biomass in metropolitan regions” contains the description of a vision on how biorefinery concepts in current and future metropoles may contribute to the increased efficiency in the use of resources for biomass production. As such this vision forms the interpretation of the principles of the circular economy within the context of biomass value chains and within the geographic boundaries of a metropolitan region. This is also referred to as the circular metropolitan system. With this paper researchers from Wageningen Food & Biobased Research intend to contribute to a scientific basis for increasing resource use efficiency in metropolitan regions through developing appropriate and sustainable biorefinery concepts.