New diet information for the giant squid (Architeuthis dux) is presented based on the identification of substantial identifiable prey items recovered from the gut contents of a specimen caught in New Zealand waters. Prey items are attributed to two species of squid: Nototodarus sp. and Architeuthis dux. The incidence of Nototodarus in the stomach contents is not new, but the occurrence of Architeuthis remains is. Numerous fragments of an Architeuthis tentacular club, consisting of carpus, manus, and dactylus suckers, and the dactylic pouch, introduce the possibility of cannibalism—a hitherto unreported behaviour in this genus. A synopsis of Architeuthis diet is presented and alternatives to cannibalism (such as autophagy) are evaluated.