ABSTRACT Background Molecular analysis of tumours may be used to identify patients predicted to benefit from targeted therapies. The Cancer Research UK Stratified Medicine programme is piloting plans to apply testing broadly across the UK healthcare system, linking molecular phenotype to clinical outcomes enabling further research and cohort identification of patients. Methods The Stratified Medicine Programme has been developed in partnership with Astra Zeneca, Pfizer, the UK Department of Health and academic researchers. Phase One is a two year feasibility study to demonstrate the collection and molecular analysis of consented sections of surplus diagnostic tumour tissue and blood samples from 9,000 patients across a network of 20 hospitals.Samples are tested for mutations in genes of potential clinical interest (KRAS, BRAF, NRAS, PIK3CA, TP53, PTEN, TMPRSS-ERG, EGFR, EML4-ALK and KIT). Different technologies are used across the three testing laboratories but all tests are technically validated with external quality assurance monitoring and targets for completion in clinically relevant timescales. Data (diagnostic including molecular information, treatment and clinical outcome) is collected through existing hospital systems, and transferred to a central data repository hosted within the Eastern Cancer Registry Information Centre. Results The study opened in September 2011 with 2160 patients consented to participate by April 2012, 607 sets of molecular results returned and planned accrual rates for Year One met (300 samples/month). Test requests and reports are exchanged electronically with standardisation of reporting being developed. Partnerships with two clinical trials for pre-screening of cohorts have been agreed.Programme accrual by tumour type. Conclusions We will report the emerging results, observations of processes and potential issues identified in delivering a scalable model for routine, high quality, prospective molecular characterisation of tumours for cancer patients, with consent for the collection, storage and research use of population-scale genetic and outcomes data. Table 1 . Programme accrual by tumour type Year one targets Patients consented Breast 641 455 Colorectal 644 263 Lung 641 610 Melanoma 213 150 Ovary 200 132 Prostate 660 529