The purpose of this study was to evaluate the efficacy and safety of an adult hyperglycemic crises protocol based upon the 2009 American Diabetes Association (ADA) consensus statement. We performed a retrospective review of patients treated before and after protocol implementation at a university teaching hospital. A total of 256 adult patients met the criteria for diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS) and were treated with an insulin infusion between February 2011 and February 2012 (nonprotocol n = 143, protocol n = 113). Protocol efficacy was evaluated by assessing time to resolution of DKA or HHS, length of stay (LOS) in the intensive care unit (ICU), and LOS in the hospital. Protocol safety was evaluated by assessing the numbers of patients with hypoglycemic and hypokalemic events. Patients on the hyperglycemic crises protocol experienced a 9.2 hour (95% confidence interval (CI): 4.70-13.70; P<.001) decrease in time to resolution, with nonprotocol patients (n = 143) resolving in 22.78 hours and protocol patients (n = 113) resolving in 13.58 hours. There was no difference in safety outcomes, including the number of patients with moderate hypoglycemia (blood glucose <70 mg/dL), severe hypoglycemia (blood glucose <50 mg/dL), or hypokalemia (K+ <3.3 mmol/L). Implementation of a hyperglycemic crises protocol decreased times to resolution of DKA and HHS without increasing the rate of hypoglycemia or hypokalemia.