Abstract: A detachable balloon catheter comprising a sealing valve assembly having an elongated passageway extending therethrough, an inflatable balloon having a mouth portion which is bonded to the periphery of the sealing valve assembly, and a small diameter cannula having a distal end which extends through the passageway in the sealing valve assembly. The small diameter cannula includes a connector terminal on the proximal end which is adapted to be coupled to a source of fluid pressure. The sealing valve assembly includes a valve mechanism which permits the passage of the cannula through the passageway but prevents the flow of fluid through the passageway when the cannula is removed. The balloon catheter also includes a cannula retainer mechanism which is formed of a resilient material and has an annular cavity for frictionally engaging the outer surface of the distal end of the cannula so that a predetermined force is required to withdraw the cannula from the retainer mechanism.