Abstract Background and Aims Rapidly progressive glomerulonephritis (RPGN) encompasses a group of diseases with a common histology in which the absence of treatment progress to end-stage renal disease. Induction treatment includes the use of immunosuppressants, and in certain cases, plasmapheresis. The final objective of this study was to determine the long-term prognosis of the RPGN. Method A retrospective observational study was conducted, including patients diagnosed with RPGN between 2004 and 2019. Baseline epidemiological data and comorbidities were collected, as well as renal function and treatment at the time of diagnosis. During the follow up [median of 42 (5-101 months)], we analyzed the evolution of renal function, mortality and associated factors. Results Forty-three patients (65% women) were included, with a mean age of 70 ± 16 years. At the time of diagnosis, mean creatinine was 4.8 ± 2.6 mg/dl, proteinuria 1094 ± 856 mg/day and 37 patients (86%) presented hematuria Thirty-one patients (72%) presented positivity for antibodies against the neutrophil cytoplasm, 7 (16%) for antibodies against the glomerular basement membrane and 5 (12%) for both. Regarding the induction treatment, 41 patients received cyclophosphamide and corticoids and two patients received rituximab. Seventeen (31%) plasmapheresis were performed with a median of 7 (6-7 sessions). At 6 months, 55% of the patients presented remission (15 patients complete remission and 8 patients partial remission). The median creatinine was 1.9 (1.2-3.1) mg/dl and the proteinuria was 380 (85 -542) mg/day (p<0.0001 compared to the initial data). At that time, 21% (9) of the patients needed dialysis. Associated factors with the absence of remission were diabetes mellitus (p= 0.016), creatinine at diagnosis (p= 0.002) and the need for hemodialysis at admission (p<0.0001). The only independent predictor of remission was initial creatinine (HR 0.5 [0.3-0.9], p= 0.048). During follow up, renal function improved with a median of creatinine at 18 months of 1.6 (1.2 – 2.9) mg/dl and 1.5 (0.8-2.4) mg/dl at the end. Twelve (28%) patients died during follow up. Associated factors with mortality were age (p=0.02), the need for hemodialysis (p=0.015) and the absence of remission at 6 months (p=0.012) (figure 1). An adjusted model using Cox regression demonstrated that the absence of remission was an independent predictor of mortality (HR 0.2 [0.5-0.8], p= 0.032). Conclusion Initial renal function and 6-month remission predicts mortality in the RPGN.