BACKGROUND: Neuro-ophthalmological complications of lymphoma are numerous and occur mostly in the setting of a known lymphoma or as the sign of a recurrence. We report the case of a woman who presented a simultaneous bilateral optic neuropathy as the initial clinical manifestation of a non-Hodgkin malignant lymphoma. HISTORY AND SIGNS: An 87-year-old patient presented simultaneous bilateral visual acuity loss, dyschromatopsia, visual field defects and frontal headaches. Pallid disc swelling was present in both eyes with peripapillary hemorrhages. Bilateral anterior ischemic optic neuropathy was diagnosed, and giant cell arteritis was suspected. Temporal artery biopsy was negative. Marked visual improvement occurred after 24 hours of intraveinous methylprednisolone therapy, and vision completely recovered within a week. THERAPY AND OUTCOME: Four months later, vision deteriorated again with bilateral pallid disc swelling. Blood studies revealed hyperleucocytosis (56 G/L) with 94 % lymphocytes. General investigations revealed a low-grade non-Hodgkin disseminated lymphoma. CONCLUSIONS: Bilateral steroid-responsive anterior optic neuropathy can be the initial manifestation of systemic lymphoma, but this case illustrates the diagnostic dilemma of some anterior optic neuropathies.