Background and Objective; Peroxiredoxins (Prxs) are a ubiquitous family of antioxidant enzymes that control cytokine-induced peroxide levels which mediate signal transduction in mammalian cells. But, the role and expression of Prx isoforms in cardiovascular system were not known. We investigated protein expression pattern of six Prx isoforms in 3 different cell types of cardiovascular system including neonatal rat cardiomyocytes (CMCs), rat vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs) with or without hydrogen peroxide. Methods; Under the concentration of 0.1 mM of hydrogen peroxide, neonatal rat CMCs (3���10⁵ cells), VSMCs (5���10⁵ cells) and HUVECs (5���10⁵ cells) were incubated for 2 hours. We evaluated the expression pattern of six Prx isoforms (Prx 1~6) by Western blot. Results; Hydrogen peroxide-induced apoptotic cell death was more increased than control. After hydrogen peroxide treatement, Prx1, 2 and 5 expressions of CMCs were downregulated. But, Prx 6 expression of CMCs was significantly increased. In VSMCs, Prx 5 was decreased where as Prx 2 was not changed. In HUVECs, Prx-6 was downregulated where as Prx 1, 2, 3 and 4 were not changed. Prx-6 expression of CMCs was increased at time-dependent manner. Conclusion; Expression patterns of six Prx isoforms in 3 different cell types were different. Theses findings suggest that selective regulation of Prx sioforms is required for the cell specific anti-oxidative defense.