Global demand for mineral fertilizers is continuously increasing, while large amounts of organic wastes are being disposed without use as a resource, resulting in soil, water and air pollution. Current trends of intensification, expansion and agglomeration of livestock production result in a net import of nutrients that lead to a surplus in some production areas. Therefore, new processes and technologies to recover and re-use nutrients from both solid and liquid wastes are desirable to close the loop on the nutrient cycle in modern human society and address future scarcity of non-renewable nutrients and fossil-based fertilizers. This Research Topic aims to present scientific progress regarding processes and technologies that allow recovery and re-use of nutrients from wastes, the selective recovery of mineral nutrients (ammonia and phosphates), the production of new organic fertilizers, and evaluation of their relative agronomic efficiency. The articles within provide a stronger recognition of the importance of nutrient recovery and upcycling in the new horizons of the circular economy.