Current guidelines suggest treatment with corticosteroids (CS) in IgA nephropathy (IgAN) with persistent proteinuria >1 g/day despite 3–6 months of supportive care and eGFR >50 ml/min/1.73m2. Whether the benefits of this treatment extend to patients with an eGFR<50 ml/min/1.73m2 is unclear. We retrospectively studied the effect of steroids on disease progression and proteinuria in IgA N patients with eGFR < 50ml/min/1.73m2 compared to those with >50ml/min/1.73m2.