Proteinuria is commonly observed in patients with chyluria due to Bancroftian filariasis. However, whether or not hypoalbuminemia is caused by chyluria alone is still a matter of debate. This is because various forms of glomerulonephritis are complicated in such patients. Herein, we report a case we have recently encountered. A 72-year-old male was admitted to our division for further evaluation of nephrotic syndrome. He was from the Southernmost part of Japan, where Bancroftian filariasis has been epidemic, and had developed persistent chyluria over a period of nearly 50 years. There was no other past history of illness except for diabetes mellitus(DM) pointed out 3 months prior to admission. The physical and laboratory examinations on admission fulfilled the diagnostic criteria for nephrotic syndrome. Lymphoscintigraphy showed an intense tracer accumulation in both kidneys. A renal biopsy was performed. At the light microscopic level, the glomeruli looked normal. Edema of the tubulointerstitium was noted. At the electron microscopic level, effacement of podocyte foot processes was not observed. Immunofluorescent study did not show glomerular deposition of immunoglobulins and complements. He also had persistent microscopic hematuria. Automated urinary sediment analysis by real-time confocal scanning laser microscopy revealed red blood cells of the non-glomerular type. Taken together, these findings strongly indicated that hypoalbuminemia of this patient was caused by chyluria alone. In conclusion, a report of the present case provides strong evidence that hypoalbuminemia of a patient with Bancroftian filariasis could be caused by chyluria alone.