To the best of our knowledge, this is the first report of a death associated with an overdose of quetiapine. Quetiapine overdose, alone or in combination with other medications, has resulted in QT prolongation (1), loss of consciousness (2), sinus tachycardia (3), and hypokalemia with first-degree heart block (4). All of the patients in these reports recovered with symptomatic and supportive treatment, including one patient with an overdose as high as 20,000 mg, which resulted in serum levels of 12,700 ng/ml (3). Factors possibly contributing to the death of our patient were a history of cardiac dysrhythmia and hypertensive heart disease. There was no evidence to suggest overdosing with medications other than quetiapine. Drug interactions did not appear to play a significant role in toxicity. Hence, despite quetiapine’s safety record in overdose, medical comorbidity in extreme overdoses may contribute to a fatal outcome.