A 62-year-old woman with rapidly progressive loss of visual acuity and impaired visual field was referred to our hospital and treated with corticosteroid pulse therapy, which resulted in minimal improvement. A chest computed tomography (CT) showed a tumor shadow in the right lung, and large-cell neuroendocrine carcinoma (LCNEC) was pathologically diagnosed using bronchoscopy. Western blot analysis for recoverin was negative. Cancer-associated retinopathy (CAR) was diagnosed based on the clinical manifestation, such as progressive loss of vision, a visual field defect, and the presence of cancer. The patient underwent chemoradiotherapy with a combination of cisplatin and etoposide. Although the lung tumor showed shrinking in size on CT scans, the patient's loss of visual field did not improved as much as expected. CAR is more frequently associated with small cell lung cancer than with other solid cancers. To our knowledge, this is the first case report of CAR associated with LCNEC. Unexplained retinopathy warrants careful examinations for the presence of malignancies.