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Abstract Introduction: Antineutrophil cytoplasmic antibody (ANCA) ‑associated vasculitis (AAV) is a rare cause of glomerulonephritis. Despite advances in immunosuppressive therapies, AAV with renal involvement often leads to poor renal outcomes and a high‑risk of end‑stage renal disease (ESRD). Berden classification categorizes renal histology in four classes, but performance varies across cohorts. A lack of precise findings of prognostic value led to development of ANCA Renal Risk Score (ARRS). We assessed ARRS predictive value for renal survival in a Portuguese cohort and compared it to Berden classification. Methods: Observational and retrospective study analysing cases from native AAV kidney biopsies at a Portuguese histomorphology centre (2004‑2023). Demographical data, percentage of normal glomeruli, interstitial fibrosis/tubular atrophy and estimated glomerular filtration rate (eGFR) were recorded. Samples were categorized by Berden class and ARRS. Descriptive and comparative analyses were performed. Results: One hundred fifty eight patients, 53.8 % male, with mean age of 67.1 ± 14.1 years. Median ARRS was 6.5 ± 3.6, with 10.8%, 44.3% and 44.9% being low, intermediate, and high‑risk, respectively. Overall mean time to dialysis was 20 months, renal survival at 36 months was 92.9%, 63.6% and 29.7% in low, intermediate and high‑risk groups. Patient survival did not differ between groups. ROC curves showed statistical significance for both scores, with ARRS having the highest AUC (AUC <0.72, p<0.001 vs 0.65, p=0.03). Conclusion: ARRS was effective in predicting renal survival in this cohort, outperforming Berden classification in deter-mining progression to ESRD at 36 months. Incorporating serum creatinine, treatment modalities and patient comorbidities could further improve ARRS predictive value.