We herein present the case of a 21-year-old diabetic obese woman who developed ketoacidosis following the administration of ipragliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor. At the time of admission, although her serum glucose level was only 175 mg/dL, laboratory tests showed ketoacidosis. Interestingly, hyperglycosuria persisted, even after the discontinuation of ipragliflozin. This is the first report of non-hyperglycemic ketoacidosis that might have been caused by protracted hyperglycosuria after the discontinuation of ipragliflozin. The development of non-hyperglycemic ketoacidosis should be monitored following the discontinuation of SGLT2 inhibitors, especially in patients who start to feel unwell and exhibit protracted hyperglycosuria after the discontinuation of treatment.