Reactive oxygen species (ROS) are produced naturally in plants during normal growth conditions. However, their production is accelerated manifold during various abiotic and biotic stresses. Rapid and efficient detoxification of ROS is vital to avoid any damage at cellular level. This is done by a well defined antioxidative system which comprises of various enzymes (superoxide dismutase, catalases and peroxidases) and low molecular weight compounds such as; praline, betaine, ascorbate and glutathione. Among these, ascorbate and glutathione are directly involved in scavenging of ROS. The present article will emphasize on the biosynthesis and role of ascorbate and glutathione during oxidative stress.