In this report, our findings confirmed that mitochondria were the major sources of hyperthermia-induced ROS generation in platelets. In addition, we demonstrated that mitochondrial ROS play a key role in hyperthermia-induced platelet apoptosis. We also showed that mitochondria-targeted ROS antagonists can inhibit hyperthermia-induced apoptotic events, including cardiolipin peroxidation, mitochondrial translocation of Bax, cytochrome C release, caspase-3 activation, PS exposure and ΔΨm depolarization. Decreased MnSOD protein levels and activity could play an important role in hyperthermia-induced increases in mitochondrial ROS.