A device capable of being used as both a dilator and catheter is presented. The dilator-catheter is comprised of an expandable housing having an interior wall and exterior wall with a space therebetween. A longitudinal cavity is provided through the housing, the cavity being defined by the interior wall. A preferably disc-shape retaining means is provided as an integral portion of the housing. The disc retainer is capable of greater relative expansion than the rest of the housing. Access means are also provided whereby any fluid, including air or liquid, may be delivered to the housing whereupon the entire housing will expand accordingly.