Fibrillary glomerulonephritis (FibGN) is a rare cause of progressive renal dysfunction, often leading to dialysis within a few years. A 60-year-old woman presented with a 2 month history of right-sided retro-orbital pain and recent diplopia. Laboratory testing revealed an altered renal function with increased serum creatinine and mild proteinuria. MRI of the brain revealed the presence of a soft tissue mass on the right cavernous sinus compatible with the diagnosis of Tolosa-Hunt syndrome (THS). Renal biopsy showed a pattern compatible with fibrillary glomerulonephritis. For this reason steroid therapy was initiated at a dose of 1 mg/kg/day and adjusted according to the clinical course. Neurological symptoms regressed shortly after the beginning of therapy and renal function and proteinuria remained stable for the 3 years following the withdrawal of steroid therapy. Percutaneous renal biopsy was again performed and confirmed the previous diagnosis of FibGN in association with other glomerular-lesion-like mesangial widening, thickening of capillary walls and severe arterio-arteriolosclerosis. This case report describes what is believed to first report of the association of FibGN and THS, which both responded to steroid therapy.