Phosphatase and tensin homolog (PTEN) is a tumor suppressor due to its ability to regulate cell survival, growth and proliferation by down-regulating PI3K/AKT signaling pathway. In addition, PTEN plays an essential role in other physiological events associated with cell growth demands, such as ischemia-reperfusion, nerve injury and immune response. Therefore, recently PTEN inhibition has emerged as a potential therapeutic intervention in these situations. Increasing evidence demonstrates that reactive oxygen species (ROS), especially hydrogen peroxide (H2O2), are produced and required for the signaling in many important cellular processes under such physiological conditions. ROS have been shown to oxidize PTEN at the cysteine residue of its active site, consequently inhibiting its function. Here we provide an overview of studies that highlight the role of oxidative inhibition of PTEN in physiological processes.