Introduction: To describe trends in incidence, age and primary renal diagnosis (PRD) at start of renal replacement therapy (RRT) in the UK for all patients aged <16 years. Material and methods: Retrospective analysis of patients aged <16 years from all 13 paediatric nephrology centres commencing RRT between 1995 and 2013 from UK Renal Registry (UKRR) data. Results: 2027 children commenced RRT between 1995 and 2013, with average annual RRT incidence between 103 and 129 patients per year. Peak age groups at commencing RRT were 12 - <16 years (33%) and 8 - <12 years (21.9%). A trend towards earlier onset of RRT over time was observed, however this did not reach statistical significance (p=0.2). The most frequent PRDs overall were renal dysplasia (27.2%) and glomerular disease (20.5%). We observed a highly statistically significant change in the distribution of PRDs by time period over the study duration (p < 0.0001). Table 1 depicts an extract of salient changes in PRD from 1995-1999 and 2010-2013. Table 1: Incidence of PRD by time period for the diagnoses with maximum change over study duration. Incidence (%) PRD 1995-1999 2010-2013 Renal Dysplasia 24.95 31.43 Glomerular Disease 21.65 13.57 Reflux Nephropathy 8.87 3.1 Drug Nephrotoxicity 4.86 0 The decline in glomerular disease and nephrotoxicity may be attributable to improved treatment and preventative medicine. The decrease in reflux nephropathy and increase in renal dysplasia possibly reflects changes in common diagnostic criteria and improved diagnostics. Conclusions: Although the incidence of established renal failure (ERF) in childhood is predominantly stable, there are discernable changes in the underlying causes with structural renal disease dominating as glomerular disease, reflux and nephrotoxicity become less frequent and a trend to younger age at start of RRT. Further research would be valuable to explain the changes seen and in planning services for children with ERF.