Antineutrophil cytoplasmic antibody-associated systemic vasculitis (AASV) frequently leads to end-stage renal disease (ESRD). Potentially fatal disease activity can continue after the onset of ESRD in both dialysis and transplant patients, despite the immunosuppressive effects of uremia and rejection prophylaxis, leading to concerns that such patients have greater morbidity and mortality. To assess the outcome of AASV patients receiving renal replacement therapy, a retrospective analysis of 59 patients from our unit who received chronic dialysis, renal transplantation, or both, was performed. The survival of AASV patients with ESRD was comparable to national registry controls, as were both graft and patient survival after renal transplantation. Ther is no evidence that standard immunosuppressive protocols should be altered for AASV patients receiving renal transplants. The rate of relapse of vasculitis for patients on chronic dialysis and after transplantation was 0.09 and 0.02 per patient per year, respectively. These rates are lower than those of other series and support the contention that continued immunosuppression after ESRD, as practiced in our unit, is warranted. Relapses usually responded to cyclophosphamide and high-dose prednisolone treatment. Significantly, vasculitic flare-ups in dialysis patients were sometimes initially misdiagnosed as dialysis complications, leading to fatal delays in effective treatment. Follow-up by physicians experienced in the diagnosis and treatment of vasculitis activity should continue in these patients.