This discovery set of tumours cancers with whole-genome sequence data comprised 14 bladder cancers, paired with peripheral blood, that had been collected from unrelated individuals presenting to the Urology Department, Royal Hallamshire Hospital, Sheffield between June 2008 and September 2011. Four cancers were of low-grade papillary morphology (pTaG1-2), five were high grade invading the lamina propria (pT1G3, with two subsequently becoming muscle-invasive); and five were muscle-invasive (pT2-pT3). All tumours were sampled at transurethral resection or cystectomy and had not previously received any other therapy. The presence of a majority of cancer cells in the tumour specimens was confirmed by routine histological assessment. Genomic DNA was extracted from each tumour and paired blood sample using standard methods.