Because of the inherent complexity of urban brownfield regeneration projects, achieving sustainability objectives is not easy. It requires approaches adapted to the specificities of this type of operation, that allow for structured and regular follow-up, and that are integrated into the project dynamics. In this chapter, we argue that sustainability monitoring can help address this challenge. We start by defining the principles of sustainability evaluation and monitoring. Then, we look deeper at the challenges of an operational monitoring tool from the brownfield regeneration perspective. On this basis, we plead for the necessity of tailor-made operational monitoring tools for this type of operation and define, to this end, three general requirements for said tools. Finally, we make a critical analysis of existing certifications at the neighbourhood scale and different approaches developed for brownfield regeneration projects.