Antineutrophil cytoplasmic autoantibody (ANCA)-associated pauci-immune glomerulonephritis (GN) is the most common finding in very elderly patients biopsied for acute kidney injury. Appropriate treatment strategies in this age group are currently undefined since it is unclear whether the benefits of immunosuppression exceed the risks. We retrospectively evaluated a cohort of 78 cases of biopsy-proven pauci-immune GN in individuals aged >80 years of whom 72% were p-ANCA and 20% were c-ANCA positive. The patients treated with immunosuppression had a significantly lower incidence of end-stage renal disease (ESRD) 1 year after biopsy (36%) compared with untreated patients (73%; P=0.03). Only peak serum creatinine before biopsy and the use of immunosuppression influenced progression to ESRD. There was no significant difference in the 1-year mortality rates between these groups (46 vs 64%; P=0.3). However, when follow-up was extended beyond 2 years, immunosuppression was associated with a lower risk of death (HR 0.33, 95% CI 0.11-0.97) and death or ESRD (HR 0.16, 95% CI 0.06-0.42) in multivariable models.