The patient was a 75-year-old man who was admitted to our hospital because of fatigue, leg edema and heavy proteinuria. Due to his cloudy urine and elevated triglyceride level in his urine, he was diagnosed with chyluria. Tests for infectious disease were negative, and lymphoscintigraphy showed no blockage in the lymphatic system. He was therefore diagnosed with idiopathic chyluria. Hypothyroidism was also found and his cloudy urine and heavy proteinuria disappeared without dietary modifications after starting levothyroxine treatment for hypothyroidism. The patient is currently being followed up in an outpatient clinic and is doing well, with no recurrence of chyluria.