BAG Barcelona has a long tradition of accessing the ESRF. It is constituted by 10 groups that belong to the Institute of Molecular Biology Barcelona from the Spanish Research Council (IBMB-CSIC), the Institute for Research in Biomedicine (IRB), and the Research Institute from Hospital Santa Creu i Sant Pau (HSCSP-IR). The main subjects of research are protein/DBA complexes, molecular machines, compounds of viruses, molecular mechanisms of proteases, and other enzymes. Recently, a new group (E. Marcos) interested in de-novo designed protein scaffolds has joined the BAG. Our Scientific results strongly rely on the high-quality data and excellent performance and support of ESRF macromolecular crystallography beamlines.