The Chronic Fatigue Working Group, led by Dr Jose Alegre at Vall d’Hebron Institute of Research (VHIR), held the first meeting with the UK ME/CFS Biobank in order to create and standardize a biobank on Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) at Vall d’Hebron University Hospital.Vall d’Hebron has the highest number of biological samples in Spain, from more than 1,600 CFS/ME patients collected over the last 20 years, according to the diagnostic criteria established by "http://www.ncbi.nlm.nih.gov/pubmed/?term=The+Chronic+Fatigue+Syndrome%3A+A+Comprehensive+Approach+to+its+Definition+and+StudyThe+Chronic+Fatigue+Syndrome%3A+A+Comprehensive+Approach+to+its+Definition+and+Study" Fukuda et al. in 1994.The aim of the meeting was to establish the same diagnostic criteria and the same methodologies and laboratory parameters, so that VHIR researchers could collect and exchange samples with international biobanks in order to get consistent results. Dr. Alegre reported that “this initiative could revolutionize the understanding of this still poorly-understood disease and enhance development of new diagnostic biomarkers and treatments”.At this first meeting, leaders of both biobanks talked about the methodology and processing to collect human biological samples for use in research (blood, DNA, RNA, urine, cerebrospinal fluid, mononuclear cells (PBMC) and tissues such as brain and muscle). Afterwards, they shared the most appropriate methods to compare the immunological assays of fresh whole blood with frozen cells from the same patient. Finally, the meeting ended with a discussion about the ethical, social and legal issues that a biobank must accomplish.The UK ME/CFS Biobank, located at the "http://www.lshtm.ac.uk/" London School of Hygiene & Tropical Medicine (LSHTM), was founded in 2004 and it is the first repository of human biological samples from patients with ME/CFS in the world.