Type 2 diabetes mellitus is a common metabolic disorder that has become a major public health problem because of the long-term microvascular and macrovascular complications associated with it. Tight glycaemic control has been shown to prevent complications, but a number of studies have shown that many patients with Type 2 diabetes have sub-optimal control. Insulin resistance is a fundamental abnormality in Type 2 diabetes but there have not been drugs that are able to reverse this defect. Thiazolidinediones (TZD) may, therefore, represent a breakthrough in the management of Type 2 diabetes as it is the first class of oral agents for diabetes that act as an insulin action enhancer to reduce insulin resistance. This review will examine available data on the currently available TZDs and consider its place in the management of Type 2 diabetes.