The Web of Science Group, a company linked to Clarivate Analytics, annually publishes a ranking of the world's most cited scientists during the last year. To elaborate it, the number of citations during the last decade is used to identify the most influential researchers in different scientific disciplines and social sciences. In 2020, the ranking has recognized two researchers from the Vall d'Hebron Research Institute (VHIR): Dr. Xavier Montalban, Head of the Clinical Neuroimmunology Service at the Vall d'Hebron University Hospital, head of the Clinical Neuroimmunology Research Group at VHIR and director of the Multiple Sclerosis Center of Catalonia (Cemcat), and Dr. Francisco Guarner, principal investigator of the Research Group in Digestive Physiology and Pathophysiology at VHIR.The ranking also includes three other scientists from the Vall d'Hebron Hospital Campus: Dr. Josep Tabernero, Head of the Medical Oncology Service of the Vall d'Hebron University Hospital and director of the Vall d'Hebron Institute of Oncology (VHIO), Dr. Enriqueta Felip, Head of Section of the Medical Oncology Service and Head of the Thoracic Tumors Unit of the Vall d'Hebron University Hospital and principal investigator of the VHIO Group of Thoracic Tumors and Head and Neck Cancer, and Dr. Javier Cortés, researcher at VHIO.Citation analysis identifies the most influential researchers as determined by their peers around the world, and those who have steadily gained recognition in the form of high citation counts over a decade. The Web of Science serves as a platform for the lists of researchers, the records of citations which place them in the top 1% in their respective groups. Their consistent production of highly cited articles reflects their essential contributions and the usefulness of their work, repeatedly judged by his peers.In the 2020 ranking there are 6,167 researchers from more than about sixty countries. This list includes 26 Nobel laureates and 66 "Clarivate Analytics Citation Laureates", individuals who, through the analysis of citations, this company has identified as "Nobel-class" researchers and potential future winners of the prestigious award.