Rosiglitazone is a new member of the thiazolidinediones (TZDs), a class of drugs which act by binding to peroxisome proliferator activated receptor gamma (PPAR-gamma). It has been suggested that the TZD class od anti-diabetic drug may exhibit anti-atherosclerotic effects. The aim of this study is to evaluate over a 12 month period the potential benefits of rosiglitazone on carotid artery atherosclerotic plaques in the type 2 diabetic population with coexisting vascular disease or hypertension. It is hypothesised that treatment with rosiglitazone will lead to a decrease in plaque size. In addition it is hoped that rosiglitazone will have a positive effect on the plaque composition and stability.