Paraneoplastic optic neuritis is a rare phenomenon that often presents as a diagnostic challenge. It has been mostly reported with small cell cancers or thymoma. Prompt treatment of the malignancy is the only effective therapy for the condition. Visual loss, once established usually becomes irreversible. We here report a case of paraneoplastic optic neuritis in a 40-year-old female with periampullary carcinoma. This is probably the first report of this association in the medical literature.