Ants (Hymenoptera: Formicidae) are diverse and ubiquitous and the ability of certain species to sting is familiar to many of us. Despite this, the venoms of ants have, until now, remained largely unstudied. I will present the first comprehensive characterisations of ant venom, those of the giant red bull ant, Myrmecia gulosa¹ and the “Green ant” Rhytidoponera metallica. Their venoms are each composed of a suite of novel peptides, which, like those of many other animal venoms are found with various post-translational modifications, including disulfide bond formation, dimerization and glycosylation. The majority of ant venom peptides show sequence features suggestive of a capacity to form amphipathic helices, and are derived from what appears to be a single gene superfamily (named the aculeatoxins) that includes most venom peptides previously reported from the Aculeate Hymenoptera. Most of these aculeatoxin peptides appear to act by targeting cell membranes where they generate a leak in membrane ion conductance altering membrane potential, which in excitable cells, triggers depolarization. A second family of epidermal growth factor (EGF)-like peptides appear to sensitize nociceptors via EGF receptors. Together, the actions of these peptides are responsible for the pain associated with stings from these ants. These data advance our understanding of the composition and mechanism of action of Hymenopteran venoms and tell us something new about our own pain physiology.