IgA Nephropathy (IgAN) is characterized by mesangial deposition of dominant, polymeric, galactose-deficient IgA1 molecules of gut-associated lymphoid tissue origin. We sought to evaluate the efficacy of targeting the mucosal immune system dysregulation underlying IgAN pathogenesis with a pH-modified formulation of budesonide with a maximum release of active compound in the distal ileum and proximal colon.We did a retrospective study evaluating the efficacy of budesonide (Budenofalk) in the treatment of IgAN. From a retrospective cohort of 143 patients with IgAN followed in our department we identified 21 patients that received treatment with budesonide. These patients received budesonide at a dose of 9 mg/d in the first 12 months, followed by a dose reduction to 3 mg/d for the subsequent period. Only patients that received a 24-month treatment with budesonide were included in the analysis (n = 18). We matched the budesonide-treated cohort to 18 patients with IgAN treated with systemic steroids from the same retrospective cohort. Efficacy was measured as change in proteinuria, hematuria and estimated glomerular filtration rate over a 24-month period.Treatment with budesonide was associated with a 24-month renal function decline of -0.22 (95%CI, -8.2 to 7.8) ml/min/1.73m, compared to -5.89 (95%CI, -12.2 to 0.4) ml/min/1.73m in the corticosteroid treatment group (p = 0.44, for between group difference). The median reduction in proteinuria at 24-month was 45% (interquartile range [IQR]: -79%; -22%) in the budesonide group and 11% (IQR: -39%; 43%) in the corticosteroid group, respectively (P = .009, for between group difference). The median reduction in hematuria at 24-month was 72% (IQR: -90%; -45%) in the budesonide group and 73% (IQR: -85%; 18%) in the corticosteroid group, respectively (P = .22, for between group difference). Treatment with budesonide was well tolerated with minimal side effects.Budesonide (Budenofalk) was effective in the treatment of patients with IgAN at high-risk of progression in terms of reducing proteinuria, hematuria and preserving renal function over 24 months of therapy.