The stomach contents of 496 Antarctic toothfish (Dissostichus mawsoni) captured by bottom longline in the western Ross Sea during the 2003 summer fishing (from Dec 2002 to Jun 2003) season were analysed. Fish sampled were caught in 770-1890 m depths and ranged between 72–212 cm in total length. D. mawsoni feeds on a wide range of prey but is primarily piscivorous. The most important prey species was Whitson’s grenadier (Macrourus whitsoni), which dominated the overall diet. In continental slope waters, M. whitsoni, the icefish Chionobathyscus dewitti, eel cods (Muraenolepis spp.) and cephalopods predominated in the diet, while on oceanic seamounts M. whitsoni, violet cod (Antimora rostrata) and cephalopods were important.