Cardiovascular complications are the main causes of mortality in diabetic patients. Teneligliptin is a newly developed anti-diabetic agent. It has been reported that teneligliptin has a vascular protective capacity in preclinical studies and diabetes patients. In this study, we investigated the effect of teneligliptin on hypoxia/reoxygenation (H/R)-induced endothelial cell injury in rat cardiac microvascular endothelial cells (CMECs). We showed that teneligliptin pretreatment suppressed H/R-induced production of reactive oxygen species (ROS), NADPH oxidase 4 (NOX4) expression and promoted glutathione production. Teneligliptin pretreatment reduced H/R-induced LDH release and improved cell viability. Teneligliptin significantly relieved the reduction in mitochondrial membrane potential (MMP) induced by H/R. Moreover, teneligliptin suppressed H/R-induced cytokine production and production of vascular adhesion molecules such as IL-1β, TNF-α and ICAM-1. Mechanistically, we showed that teneligliptin inhibited the expression of transcriptional factor Egr-1, which regulates cytokine production and vascular adhesion. Collectively, our data support the notion that teneligliptin is a protective agent in CMECs and has the potential for therapeutic use in the treatments of vascular complications in diabetes patients.