Background The sodium-glucose cotransporter-2 (SGLT2) inhibitors are the newest class of anti-hyperglycemic medications used in the treatment of diabetes mellitus. Their increasing use has been driven by their apparent cardiovascular and renal benefits. They have been associated with a small but significantly increased risk of diabetic ketoacidosis (DKA). Many of the cases of DKA associated with SGLT2 inhibitor use present with normal or minimally elevated serum glucose levels, often delaying the diagnosis. Case presentation A 44-year-old woman with diabetes mellitus presented to our emergency department complaining of 3 days of generalized weakness. The SGLT2 inhibitor canagliflozin had been added to her medication regimen 4 weeks earlier, and she had stopped using insulin 2 weeks prior to presentation. Laboratory evaluation revealed a metabolic acidosis with an elevated anion gap and the presence of serum acetone, despite a minimally elevated serum glucose of 163 mg/dL. The patient was treated for euglycemic DKA with intravenous infusions of insulin and dextrose, with resolution of her symptoms in 3 days. Conclusions The SGLT2 inhibitors are a novel class of anti-hyperglycemic medications that are being used with increasing frequency in the treatment of diabetes mellitus. They are associated with a small but significantly increased risk of DKA. Many of the patients presenting with DKA associated with SGLT2 inhibitor use will have normal or minimally elevated serum glucose levels. This unusual presentation of DKA can be diagnostically challenging.