This article describes case studies of five children treated with vasopressin for refractory hypotension. In addition, physiology and pharmacology of vasopressin are reviewed in a comprehensive survey of the literature from 1966 until the present. In all five children, blood pressure increased immediately after vasopressin administration. The preliminary success of vasopressin for hypotension the setting of vasodilatory shock is promising. This limited use of vasopressin in the setting of refractory hypotension in these patients appears to be safe; the appropriate patient population and dose regimen are not yet determined.