The elderly are more often referred to nephrologists and questions about indications for renal biopsy are increasing. The vascular lesions that appear with aging make the diagnosis of additional nephropathy more difficult. The purpose of our study is to investigate the characteristics of renal biopsies in the elderly in order to evaluate the indications and their use in guiding specific therapeutic interventions. Patients over 70 years who underwent a renal biopsy between 2000 and 2007 in Rennes University Hospital were retrospectively analyzed for biopsy complications, clinical features, diagnosis, therapy and its complications, evolution and mortality. Among the 150 renal-biopsied patients, 60% had a glomerulopathy and 30% had nephrotic syndrome. Biopsy complications occurred in 3.3%. 64% of nephrotic patients received immunosuppressive treatment and 62% of them developed drug-associated complications. In the treated group, there was more remission and survival at day 1000 was improved. Renal biopsy may be indicated in the elderly, because it often gives a therapeutically useful diagnosis and complications are rare if contra-indications are respected. Kidney biopsy revealed histological diagnoses that were not usually suspected by the clinical presentation. In addition, immunosuppressive therapy did not alter the mortality rate, but did increase survival at 3 years.