Some academic research projects have been developed in Universidad de Guanajuato, in Guanajuato state (México) and in Universitat Politecnica de Catalunya, in Catalunya (Spain) related to circular economy applied to pigs, especially in the process developed in slaughterhouses. The project aims to create a proposal for a complete valuation of every waste and for the use of every part of the pig, so the cycle in the pig’s slaughterhouse is completely closed. In this way the projects contribute to the circular economy. To achieve it, two students in Mexico (Master in Water Science and Grade in Environmental Engineering) and three in Catalonia (Master I Environmental Engineering and Master in Sustainability) have completed their theses. They have also helped to initiate a biomass growing pilot plant to test some of the waste valuations. First, some visits to slaughterhouses and to waste valuation facilities in Mexico and Catalonia were held. Afterwards, a flow diagram of the pig’s slaughterhouses was drawn for each country. Then, the attention was paid into wastes and how they were reused, recycled or disposed. The present reuse or recycling of waste is considered an existing synergy. Finally, some proposals were considered in order to close the material cycle in the pig slaughterhouses, so some new synergies were suggested, and the proposed synergies diagram was drawn. Some of the waste valuation proposals were tested in a pilot plant. Although the whole project is still active, there are some preliminary results: 16 existing synergies have been figured out and 27 synergies have been suggested. Some of the proposed synergies are: protein and ferrous products extracted from blood, construction panels and compost made from pig hair, insulin extracted from the pancreas, among others. The waste valuation undertaken was the use of pig slaughterhouses wastewater to grow biomass. This biomass is used afterwards to produce pig food, so the closure for the pig cycle is achieved. Students are very satisfied with these academic research projects, as they are able to experiment and to put into practice some of the new proposals for the circular economy