Renewable fuels have been identified as a viable alternative to replace its fossil counterparts without modification in the existing internal combustion engines. These renewable fuels, also known as biofuels, are obtained from the processing of biomass through several conversion pathways. Regard the biomasses, they can be virgin or residuals, edible or non-edible; nevertheless, waste biomass is preferred since there is no competition with food safety as well as land and water resources. Moreover, the use of waste biomasses for renewable fuels production allows to solve a pollution problem and to generate energy; so, it is a strategy aligned to circular economy model. However, the production of biofuels must as well follows the principles of circular economy. Therefore, in this chapter the principles of circular economy as well as its potential application for renewable fuels production processes are presented.