We report a rare case of idiopathic chylothorax and chyluria. A 31 year-old woman was referred to our hospital with a right-sided pleural effusion. Cream-colored pleural fluid and urine were confirmed as chylothorax and chyluria, respectively, by a lipoprotein electrophoresis. Even though she had previously underwent surgery for pelvic fibrosarcoma and experienced its recurrence, there has been no change of mass size and no evidence of thoracic duct or urinary tract obstruction as of the moment. Hence, idiopathic chylothorax and chyluira was diagnosed. Because she responded poorly to conservative treatment, thoracic duct ligation and pleurodesis were performend ; wherease chyluria was resolved spontaneously.