Background: The purpose of this study was to investigate the prevalence of rhabdomyolysis and its association with both clinical course and prognosis and to evaluate the factors associated with rhabdomyolysis in patients with hyperglycemic emergencies. Methods: We reviewed the medical records of patients with hyperglycemic emergencies who visited our hospital from May 2003 to April 2010. We assessed the clinical characteristics, biochemical profiles and clinical course of patients and analyzed these data according to the presence of rhabdomyolysis. Results: The prevalence of rhabdomyolysis was 29 patients (28.4%) among 102 patients. Mean serum osmolarity, glucose and serum creatinine levels were higher in patients with rhabdomyolysis than those without rhabdomyolysis. Patients with rhabdomyolysis had higher rates of hemodialysis and mortality than those without the condition. The factors associated with rhabdomyolysis in the hyperglycemic emergency state were increased serum osmolarity and APACHE II score on admission (P < 0.05). Conclusion: Rhabdomyolysis commonly occurred in patients with hyperglycemic emergencies and this could aggravate their clinical course and increase mortality. (Endocrinol Metab 26:317-323, 2011)