BACKGROUND AND OBJECTIVES: The Osborn wave is the name designated to the wave formation produced when there is a large, prominent deviation of the J point from the baseline. The wave has been reported in many countries, but only 2 cases have been reported in Korea. Thus, the purpose of our study was to evaluate the clinical characteristics and therapy of hypothermia employing the Osborn wave with Koreans. SUBJECTS AND METHODS: Between February 2001 and April 2001, five patients visiting our department with hypothermia were enrolled in this study. We analyzed these patients for their distribution, symptoms and signs, associated disorders, risk factors, electrocardiogram and laboratory findings. RESULTS: All 5 patients were male with an average age was 44.8+/-12.7 years. Three patients had a semi-comatose mentality and 2 cases had a comatose mentality. Their associated disorders were diabetes (2 cases), psychotic problems (1 case) and nutritional deficiency (1 case). Risk factors were alcohol abuse (3 cases) and drug in toxication (1 case). Laboratory abnormalities were acidosis (4 cases), increased serum glucose levels (all 5 cases) and increased serum potassium levels (3 cases). After active core rewarming by a line heat exchanger, 3 of the 5 patients completely recovered from hypothermia, 1 case immediately expired following admission and 1 case survived for 10 days, but later expired due to acute respiratory distress syndrome. The Osborn wave was persistent in 1 case and disappeared in 3 cases. CONCLUSION: We experienced 5 cases of hypothermia with an Osborn wave. The mortality of patients displaying an Osborn wave is expected to decrease if this anomaly is immediately found and treated by an appropriate method.