© 2022 Turkish Society of Nephrology. All rights reserved.Objective: Advanced age, need for dialysis and high creatinine values at the time of admission, anti-glomerular basement membrane antibody positivity, pulmonary hemorrhage, and fibrous crescents on pathology are known poor prognostic factors in rapidly progressive glomerulonephritis. Our study aimed to determine the clinical, laboratory, and pathological factors affecting the kidney prognosis in the progression to end-stage kidney failure disease in our rapidly progressive glomerulonephritis patients. Methods: This study was made with 52 patients diagnosed with type 1 and type 3 rapidly progressive glomerulonephritis. The study continued with 37 eligible patients. Results: The patients’ mean age was 52.3 ± 11.06 and 22 (59.4%) were male. In 6 patients (16.2%), anti-glomerular basement membrane positivity, in 11 patients (29.7%), cytoplasmic anti-neutrophilic cytoplasmic antibody positivity, and in 20 patients (54.1%), perinuclear anti-neutrophilic cytoplasmic antibody positivity was detected. Parathyroid hormone value was higher in the perinuclear anti-neutrophilic cytoplasmic antibody-positive group at the time of biopsy (P = .005). Serum sodium levels were lower at the biopsy time in the patient group with a crescent rate above 65% (P = .014). Patients with end-stage kidney failure disease were younger, and their serum sodium levels expressively were lower at the biopsy time (P = .006, P = .02 respectively). When the risk factors affecting end-stage kidney failure disease were examined in multivariate regression analysis, it was observed that while sodium and parathyroid hormone values were not risk factors at the time of biopsy, age (P = .048) and time until diagnosis were risk factors (P = .048). Conclusion: In our study, the risk factors affecting end-stage kidney failure disease progression in rapidly progressive glomerulonephritis patients were age and the time until diagnosis. Kidney biopsy is essential for the kidney prognosis for rapid diagnosis, especially in young patients with suspected rapidly progressive glomerulonephritis.