Objective: Patients with hypothermia are frequently admitted to the intensive care unit. Hypothermia may be associated with typical ECG changes (Osborn waves). Here, we present a typical case report with sequential ECG examinations from hypothermia to normothermia. Design: A case report. Patient: A 56-year-old woman was hospitalized with prolonged hypothermia after a suicide attempt with oxazepam and paracetamol. Measurement and main results: On admission to the intensive care unit the hypothermic patient showed typical Osborn waves in II, III, AvF and all precordial leads on the ECG. During active rewarming, the Osborn waves diminished in amplitude and disappeared after six hours when her core temperature had normalized. Conclusion: Osborn waves can often be seen during hypothermia where a discrepancy in epicardial and endocardial potassium current occurs during ventricular repolarisation, resulting in a transmural voltage gradient, which is thought to be the cellular basis of the Osborn wave. © 2010. Nederlandse Vereniging voor Intensive Care. All Rights Reserved.