Increasing focus has recently been directed toward the different parameters of drug-eluting stents—stent design, delivery-vehicle materials, and drug properties—and the manner in which each of these elements may affect the function of the stents. Several specific characteristics of design may affect restenosis, although design optimization often presents a choice between acute procedural success and long-term biological stability. The influence of design parameters such as strut thickness and cell configuration is described. Polymer material has frequently been used to coat drug-eluting stents, although some agents, such as paclitaxel, can be attached directly to the stent's surface, obviating the need for a polymer layer. The properties of agents used in drug-eluting stents and how those properties affect delivery and long-term outcome are discussed, as is the influence of the disease state of the target vessel on stent safety and efficacy.