Fibrillary glomerulonephritis belongs to a group of disorders characterized by pathogenic deposition of fibrils in glomeruli. This glomerulopathy tends to progress to end-stage kidney disease, and there currently are no treatments of proven benefit, including corticosteroids and cytotoxic agents. Because the glomerular deposits contain an immunoglobulin component, it was postulated that anti-B-cell therapy with rituximab, an anti-CD20 monoclonal antibody, may be effective in the treatment of patients with fibrillary glomerulonephritis. We describe 3 patients with fibrillary glomerulonephritis who were treated with rituximab for nephrotic-range proteinuria. Each patient also received standard antiproteinuria therapy, including blockade of the renin-angiotensin system and strict blood pressure control. All patients showed a decrease in proteinuria to less than 1.5 g/d of protein by 27 months, and kidney function was preserved throughout the duration of therapy and follow-up. No adverse effects were seen with rituximab. These outcomes suggest that treatment with rituximab may be a promising approach to the management of fibrillary glomerulonephritis, an entity previously considered refractory to therapy.