Propranolol hydrochloride is a beta-adrenergic blocking drug used in a variety of clinical conditions. Overdoses can result in severe hypotensive states usually associated with bradycardia or asystole or with profound myocardial depression. We report on an 18-year-old man who ingested a massive dose of propranolol HCl in a suicide attempt. The patient was brought to the hospital in an unresponsive state within 30 minutes of ingestion. He was initially stabilized but subsequently died nine hours after the drug was ingested. Invasive monitoring during this period revealed the shock to be secondary to marked depression of his systemic vascular resistance. Cardiac rhythm and left ventricular output were maintained throughout the attempted resuscitation. This hemodynamic picture suggests that decreased systemic vascular resistance may be another mechanism of shock in significant propranolol HCl overdoses.