A stent delivery balloon 1 is used to deploy a plurality of mini-stents 5 into a bodily lumen at a controlled spacing. The balloon 1 has formations 3 for retaining the stents in a designed position. The formations may comprise ridges 3, or retractable bridging elements, on the surface of the balloon 1 to control both the expansion of the multiple stents 5 from a single balloon 1 and also the coverage of the vessel wall following stenting.