Selenium is an essential trace element and low selenium status has been associated with poor gestational outcomes. Selenium is metabolised to the amino acids Selenomethionine and selenocysteine and the latter forms the active site of some 25 selenoproteins. The majority of these can be found in the human placenta. Glutathione Peroxidases (GPx) and Thioredoxin reductases (ThxRed) have been extensively studied in the human placenta and play a role in regulating redox homeostasis. Placental oxidative stress at the mitochondrial/ER interface is increased in preeclampsia, fetal growth restriction and some cases of preterm birth. Decreased expression and specific cellular localisation of these selenoenzymes has been implicated in the development of placental oxidative stress. Whilst we know much about the important role of GPx and ThxRed in the placenta less is known of the role that other selenoproteins may play at the feto-maternal interface. This presentation will review the current data on selenium status and gestational outcomes, the importance of placental selenoproteins and propose a critical role for selected selenoproteins in responding to stress at the mitochondrial/ER interface in the human placenta.