We report a case of nephrotic syndrome with thymic neuroendocrine tumor. A 50-year-old woman was admitted with generalized edema. 24-hour urine collection revealed proteinuria of 20 gram daily and creatinine clearance of 28 mL/min. During examination, a thymic mass was found, which is unresectable due to metastasis to the lung. Biopsy of the thymus and the kidney revealed large cell neuroendocrine carcinoma of thymus origin and minimal change disease, respectively. Despite high dose steroid therapy, massive proteinuria continued for about 30 days. However, when the patient was given a chemotherapy (cyclophosphamide, adriamycin, vincristine), proteinuria began to decrease dramatically. The carcinoma showed the partial response after six cycles of chemotherapy. This is the first report on remission of malignancy-related nephrotic syndrome after chemotherapy, especially for thymic neuroendocrine tumor.