Purpose: The aim of this study was to assess the incidence of hypoglycemia in hospitalized patients following acute treatment of hyperkalemia with insulin. A characterization of the affected patients and the administered insulin/dextrose regimens was also performed. Methods: A retrospective search of the electronic records of a large university-based tertiary care hospital was conducted, from June 1, 2009 to December 1, 2009, to identify patients who developed hypoglycemia following acute stabilization of hyperkalemia treatment with regular insulin. Results: Of 219 hyperkalemic patients who met the criteria of the study, 19 patients (8.7%) were identified as hypoglycemic (blood glucose <70 mg/dl), and 5 of these patients (2.3% of study patients) were classified as severely hypoglycemic (blood glucose <40 mg/dl). Fifteen (79%) of the hypoglycemic patients had acute kidney injury or were end-stage renal disease patients on hemodialysis at the time of treatment. Fifty-eight percent of the hypoglycemic events occurred following the commonly employed 10 units of regular insulin and 25 gm of dextrose 50% treatment regimen. Conclusion: Iatrogenic hypoglycemia, as a result of treatment for hyperkalemia, is a common occurrence. Hyperkalemia occurs disproportionately in patients with acute kidney injury or end-stage renal disease, and these patients are predisposed to an increased risk of hypoglycemia. The risk of severe hypoglycemia escalates in patients with lower body weight and creatinine clearance. Hypoglycemia risk can be minimized by providing sufficient dextrose in the treatment regimen, however, patient variability in treatment response dictates careful blood glucose monitoring before and after treatment.