A balloon catheter having a balloon with a thickened wall portion extending along at least a portion of the working length section of the balloon in a noninflated configuration. The balloon has a first layer formed of a first polymeric material and a second layer formed of a second, different polymeric material, the second layer having a wall thickness which is greater along the central working length section than the wall thickness of the second layer along a section proximal and/or a section distal to the central working length of the balloon. In a presently preferred embodiment, the first layer is formed of a porous material such as expanded polytetrafluoroethylene (ePTFE), and the second layer of the balloon is formed of an elastomeric polymer. The balloon catheter has a highly flexible distal section and a relatively high strength, low profile balloon, due to the balloon configuration of the invention.