This resource will exploit the CFS/ME National Outcomes Database (NOD), which collects data at clinical assessment (2,000 cases per year) and follow-up from NHS specialist CFS/ME services in England. The NOD will have phenotypic data on ~7,000 patients with link with CFS/ME at the start of the study (October 2012). BioME will add data ~7,500 patients and link with phenotypic data collected from two large randomised controlled trials (1,2) creating a database with data on ~15,500 patients. We will contact all patients who have contributed data (2006-2012), and all new patients (2012-2017) attending 19 specialist CFS/ME services, to collect saliva samples (by post) and extract genomic DNA (~9,400 samples). Research nurses in 4/19 services will also collect blood into clotted, EDTA and PAXgene tubes (fractions: serum, plasma, buffy coat, red cells, RNA) and urine from 1,000 patients. This large collection of phenotypic data and biological samples will enable researchers to perform: genome wide assocation studies (GWAS) and epigenetic, metabolomic and proteomics studies using samples from CFS/ME patients with well-characterised phenotypes and long-term outcome data.