Abstract Background Chronic Kidney Disease is a major cause of morbidity and interventions now exist which can reduce risk. We sought to develop and validate two new risk algorithms (the QKidney ® Scores) for estimating (a) the individual 5 year risk of moderate-severe CKD and (b) the individual 5 year risk of developing End Stage Kidney Failure in a primary care population. Methods We conducted a prospective open cohort study using data from 368 QResearch ® general practices to develop the scores. We validated the scores using two separate sets of practices - 188 separate QResearch ® practices and 364 practices contributing to the THIN database. We studied 775,091 women and 799,658 men aged 35-74 years in the QResearch ® derivation cohort, who contributed 4,068,643 and 4,121,926 person-years of observation respectively. We had two main outcomes (a) moderate-severe CKD (defined as the first evidence of CKD based on the earliest of any of the following: kidney transplant; kidney dialysis; diagnosis of nephropathy; persistent proteinuria; or glomerular filtration rate of