The 4th Ibero-American Congress on Biorefineries took place at the University of Jaén (Spain) between October 24 and 26, 2018. The main objective of this congress is to promote the creation of industrial facilities for the integral use of biomass, in a sustainable way, for the simultaneous production of biofuels, energy, materials and chemical products. The Congress was a meeting of international scope of researchers and professionals, in which the latest advances in the scientific and technological field of the development of this type of facilities have been exposed. This work collects the summaries of the papers presented, in different thematic areas, ranging from the raw materials (Biomass for biorefineries) and the initial stages (pretreatments and biochemical and thermochemical platforms) to the technical-economic and environmental evaluation or the different bioproducts , as well as a chapter dedicated to a selection of current projects.