Background/Aim: Peroxiredoxin (Prx) protein family is aberrantly expressed in various cancers including gastric cancer. Among the six family members, Prx V has been known as an antioxidant enzyme which scavenges intracellular reactive oxygen species (ROS) and modulates cellular apoptosis. This study aimed at investigating the role of Prx V in apoptosis of gastric cancer cells. Materials and Methods: Stably constructed Prx V knockdown, over-expression and mock AGS cells (a human gastric adenocarcinoma cell line) were used to study the effect of Prx V on emodin-induced apoptosis by western blotting, cell viability, apoptosis and ROS detection assays. Results: Overexpression of Prx V significantly decreased emodin-induced cellular apoptosis and ROS levels compared to Mock and Prx V knockdown AGS cells. Also, overexpression of Prx V down-regulated the expression of proapoptotic proteins, Bad and cleaved PARP, and increased the expression of anti-apoptotic protein, Bcl2. Conclusion: Prx V suppresses AGS cell apoptosis via scavenging intracellular ROS and modulating apoptosis-related markers. Gastric cancer (GC) is one of the most common malignancies worldwide; unfortunately, the majority of GC patients is diagnosed at an advanced stage and die within 24 months after surgery because of recurrence and metastasis (1). The cure rate of gastric cancer is extremely low and the risk of treatment is large. It is well known that reactive oxygen species ROS levels are high in cancer cells compared to normal cells. ROS such as hydrogen peroxide, superoxide anions etc. are produced during mitochondria metabolism (2). Low levels of ROS can act as second messengers by participating in a variety of cellular physiological activities such as signal transduction, apoptosis, aging, proliferation and migration of cells. On the contrary, high levels of ROS have been recognized as driving factors in numerous diseases including cancer, aging, neurodegenerative disease, diabetes, cardiovascular disease, stroke, and asthma (3, 4), by inducing lipid, protein and DNA oxidation (5) thereby resulting in increased cellular apoptosis. On the other hand, there are cellular antioxidant mechanisms that clear excessive ROS (6, 7), such as superoxide dismutase (SOD), catalase (Cat), glutathione peroxidase (Gpx) and peroxiredoxin (Prxs). Prx V is a member of the Prxs family, which plays crucial roles in protecting cells from oxidative stress. Prxs are 1183 This article is freely accessible online.