Background: The insulin-sensitizing agents (rosiglitazone, pioglitazone) reduced neointimal proliferation in patients with diabetes mellitus (DM) who underwent percutaneous coronary intervention (PCI). We evaluated the clinical outcomes, angiographic results and intravascular ultrasound (IVUS) results of patients taking pioglitazone after PCI. Methods: This study was prospective randomized study and is in progress. The study population currently includes 46 patients taking pioglitazone (pioglitazone group) and 31 patients without piglitazone (control group) after PCI. We have analyzed the clinical outcomes, angiographic results, IVUS results and the effects on the lipid profile after 9 months of treatment. Results: There were no significant differences between the pioglitazone group and the control group of the baseline clinical demographics and angiographic findings. The pioglitazone group, at six months, had reduction of major cardiac adverse events (MACE) compared to the control group (MACE 0/39, 0% vs. 6/22, 27.2%, p=0.002). In addition, the pioglitazone group, at six months, had less frequent lesion revascularization (TLR) compared to the control group (TLR 0/39, 0% vs. 5/22, 18.7%, p=0.009). The rate of restenosis after 9 months was low in the piog1itazone group (1/9, 10% vs. 6/22, 27.3%, p=0.387).Conclusion: The results of this study showed that pioglitazone, in diabetic patients who underwent PCI, was associated with reduced MACE, TLR and restenosis. Pioglitazone pioglitazone had a positive effect on the lipid profile. Pioglitazone may improve clinical outcomes by inhibition of neointimal proliferation as well as improving the lipid profile.