Glitazones are new oral antidiabetic drugs, which started to be used in the clinical practice in the recent years. They act by activation of nuclear peroxisome proliferator activated receptors γ (PPARγ) that leads to increase in insulin sensitivity in liver, muscle and fat tissue. Beside their effect on hyperglycemia glitazones affect further signs of insulin resistance, such as dyslipidemia, increased blood pressure, proinflammatory and procoagulation states, as well as endothelial dysfunction. The results of four important studies with glitazones were published in 2006. In the Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication (DREAM) trial it was observed that rosiglitazone application in patients with impaired glucose tolerance led to a decreased incidence of type 2 diabetes (T2DM) by almost two thirds during three years. The CHICAGO study showed that 72-week pioglitazone treatment led to slower progression of carotid intima-media thickness when compared with glimepiride. In the further study, 6-month pioglitazone treatment led to improvement of metabolic and histologic signs of nonalcoholic steatohepatitis in patients with T2DM and impaired glucose tolerance. In the ADOPT (A Diabetes Outcome Progression Trial) study rosiglitazone treatment during four years led to a lower rate of monotherapy failure and better glycemic control than treatment with metformin or glibenclamide. The results of the mentioned studies suggest therapeutic potential of glitazones in diabetes prevention and treatment, as well as in the treatment of nonalcoholic steatohepatitis. Preventive effect of glitazones on atherosclerosis needs further confirmation in endpoint studies.