Abstract Background and Aims There are numerous studies on AAV, however, data describing the use of immunosuppressive treatment in AAV patients (pts) on chronic dialysis are limited. Most studies found that the incidence of infection is much higher than that of relapses (0.05-0.1 pt per year), suggesting that immunosuppression should be stopped after 3 months in pts with end-stage renal failure. Material, Method Retrospective analysis of immunosuppressive treatment in pts on chronic dialysis due to AAV. From 1995 to 2019 139 pts were diagnosed with AAV. Among them 38 patients (26 female, 12 male, mean age 58 years) needed chronic dialysis (>90 days) due to severe renal AAV (29), relapsing renal disease (6) or progressive CKD without active vasculitis (3). Results Microscopic polyangiitis was diagnosed in 20, granulomatosis with polyangiitis in 14, eosinophilic granulomatosis with polyangiitis in 4 cases. MPO-ANCA was more frequent than PR3-ANCA (23 vs 12), in one case both ANCAs were positive, and in two cases both were negative. The mean dialysis duration was 55 months (4–180 months). 18 pts (47%) had at least one relapse during the observation period. The mean age, the clinical diagnosis, the type of ANCA did not cause any difference, the dialysis time was longer in the relapsed pts group (72+/-38 vs. 40+/-29 months) compared to pts without relapse. High relapse rate was seen in 6 cases. Three patient had continuously high level of PR3-ANCA without relapse or any sign of disease. Relapses were treated mostly with combined therapy of corticosteroids and oral/intravenous cyclophosphamide followed by azathioprin maintenance therapy. Cortocosteroid alone was used in 7 pts, rituximab in five pts as maintenance therapy. Serious infection (needing hospital care) rate during any immunosuppressive treatment was 0.12 per patient-years. There were 12 deaths on dialysis, the median time to death was 61 months (range 3–132). The deaths rate was higher (9/18 vs. 4/20) in relapsed pts, 4 occurring during immunosuppressive treatment. Causes of deaths were cardiovascular (8), sepsis (3), malignancy (2 pts). Seven pts received kidney grafts, 15 pts remained on dialysis, but in three case dialysis could be discontinued after 16, 35 and 36 months. Conclusion Our study points to higher relapse rate and lower serious infection rate in AAV pts on chronic dialysis compared to previous studies. It seems reasonable to continue immunosuppression above 3 months in pts remaining on chronic dialysis. This approach may decrease the relapse rate preventing damage of other organs, allowing transplantation and in some pts recovery of renal function could be achieved.