β-Thalassemia minor is a hemoglobinopathy which has been known as a symptomless carrier state. Although there are many causes leading to renal tubular dysfunction, β-thalassemia minor has not been reported among them in reviewing the literature. In a 20-year-old male patient referred to us because of glucosuria detected with dipstick, there was also anemia (hemoglobin, 11.5 g/dl; mean cell volume, 60 fl; and mean cell hemoglobin concentration, 19.5 pg). The 24-hour urinary glucose excretion rate was 5 g and, additionally, he had tubular proteinuria (albumin/β<sub>2</sub>-microglobulin ratio in urine was 17.32). Based upon the detailed evaluation for both asymptomatic urinary abnormality and anemia, he was diagnosed as having renal tubular dysfunction and β-thalassemia minor (hemoglobin A<sub>1 </sub>was 91%, and hemoglobin A<sub>2 </sub>was 9%). In conclusion, further reports are needed to reveal whether there is an association between these two distinct disorders.