Children who suffer cardiac arrest have a poor prognosis. Based on laboratory animal studies and clinical data in adults, vasopressin is an exciting new vasopressor treatment modality during cardiopulmonary resuscitation (CPR). In particular, vasopressin has resulted in short term resuscitation benefits as a "rescue" pressor agent in the setting of prolonged out-of-hospital CPR for ventricular fibrillation in adults. This retrospective series presents the first evidence for resuscitation benefit of bolus vasopressin therapy in the specific setting of pediatric cardiac arrest. All episodes of CPR initiated in a 120-bed tertiary care children's hospital over a three-year period (1997-2000) were reviewed. Four children in the pediatric ICU received vasopressin boluses as rescue therapy during six cardiac arrest events, following failure of conventional CPR, advanced life support, and epinephrine vasopressor therapy. Return of spontaneous circulation for greater than 60 min occurred in three of four patients (75%) and in four of six CPR events (66%) following vasopressin administration. Two of four vasopressin recipients survived >24 h; one survived to hospital discharge and one had withdrawal of supportive therapies following family discussion. Our observations are AHA level 5 (retrospective case series) evidence that vasopressin administration may be beneficial during prolonged pediatric cardiac arrest. Such reports should pave the way for prospective clinical trials comparing vasopressor medications in the setting of pediatric cardiac arrest.