A balloon catheter comprises an outer shaft having a distal end, an inner shaft situated therein to form an annular fluid line and projecting beyond the distal end of the outer shaft, and a balloon which is dilatable under the influence of a fluid introduced through the fluid line under pressure. At its proximal end the balloon is attached in a fluid-tight manner to the distal end region of the outer shaft at a first attachment zone, and at its distal end is attached in a fluid-tight manner to the distal end region of the inner shaft at a second attachment zone. Between the attachment zones, in the undilated state the balloon is placed in longitudinal folds along its length. The balloon, at least at its distal end, has an untapered design with a thin wall thickness (d) which is essentially unchanged over the length of the balloon, and the longitudinal folds extend into the attachment zone at that location.