Thiazolidinediones (TZDs) are widely used in the type 2 diabetes mellitus (DMT2) treatment but have also been tested in cardiovascular prevention. DMT2 is associated with a marked increment in cardiovascular risk, and its prevention represents a main target in cardiometabolic protection. Both Troglitazone (Troglitazone in Prevention of Diabetes study) and Rosiglitazone (Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication study) significantly reduced new-onset diabetes. A similar topic will be investigated with pioglitazone (Actos Now for Prevention of Diabetes). In the Prospective Pioglitazone Clinical Trial in Macrovascular events the primary end point (all-cause mortality, nonfatal myocardial infarction, stroke, acute coronary syndromes, endovascular or surgical intervention in the coronary/leg arteries and amputation above ankles) was unaffected, whereas the secondary one (all-cause mortality, nonfatal myocardial infarction and stroke) was reduced by pioglitazone (-16%, p=0.027) compared to placebo in 5,238 patients with DMT2 and macrovascular disease. In contrast, a meta-analysis (Nissen and Wolski, N Engl J Med. 2007;356:2457-2471) reported that rosiglitazone treatment is associated with a significant increase in myocardial infarction risk (p=0.03) and a borderline significant increase in the risk of death from cardiovascular causes (p=0.06). Nevertheless, the possibility that rosiglitazone might affect cardiovascular events should be evaluated by the ongoing trial Rosiglitazone Evaluated for Cardiac Outcomes and Regulation of Glycemia in Diabetes (RECORD). Interim findings early from RECORD did not show significant differences between the rosiglitazone and the control group regarding myocardial infarction and death from cardiovascular and any cause. Additional large-scale trials are awaited to clarify the of role TZDs in cardiovascular outcomes.