Dr. Jordi Rello, head of the Clinical Research and Innovation in Pneumonia & Sepsis group (CRIPS), and Dr. Juan Carlos Ruiz, from the Shock, Organ Dysfunction & Resuscitation group (SODIR), have led the participation of Vall d’Hebron University Hospital in the "http://impress-ssc.com/" International Multicentre Prevalence Study on Sepsis (IMPRESS). IMPRESS is an observational study on severe sepsis and septic shock carried out by the European Society of Intensive Care (ESICM) and the Society of Critical Care Medicine (SCCM) under the framework of the Surviving Sepsis Campaign. Researchers from ICUs and Emergency Departments wordwide, collected the data for this study on November 7, in order to determine the incidence and clinical patterns of septic syndromes on a single day.Specifically, the aims of the study is to determine the epidemiology of severe sepsis and septic shock throughout the world, to evaluate the impact of sepsis syndromes on outcome and the implementation of treatment guidelines recommended by Sepsis Survival Campaign, and to estimate sample size requirements to detect meaningful differences in patient-centered outcomes for clinical trials performed in a large international and collaborative research network. More than 1,000 hospitals from all around the world, among them 60 Spanish hospitals, participated in this initiative in launched on the World Sepsis Day.