To present a 5-year mortal case of Waldenström's macroglobulinemia-related retinopathy and serous macular detachment. A 63-year-old man, with unremarkable medical history, presented with bilateral decreased vision for 2 months. Fundus examination revealed bilateral scattered retinal hemorrhages, exudates, venous tortuosity, and serous macular detachment. Hematologic and biochemistry profiles showed pancytopenia with blood smear demonstrating erythrocyte rouleaux formation. Hyperviscosity syndrome was suspected and later Waldenström's macroglobulinemia was diagnosed by bone marrow biopsy and high concentration of serum IgM. Plasmapheresis and subsequent chemotherapy were arranged. In spite of resolution of most retinal abnormalities, his visual acuity still showed no improvement with a persistent bilateral macular detachment. The patient then died 5 years after the diagnosis of Waldenström's macroglobulinemia. Long-term toxicity of IgM to the retinal pigment epithelium may impede the resolution of the persistent serous macular detachment, resulting in an inability of recovery in his vision. Therefore, early diagnosis and timely reduction of serum paraproteins by plasmapheresis and chemotherapy is critical for preventing permanent damages to patients' health and vision.