The diet of juvenile (< 800 mm TL) Patagonian toothfish (Dissostichus eleginoides) was investigated using stomach contents analysis of fish caught in research trawls on the South Georgia and Shag Rocks shelves in the Atlantic Sector of the Southern Ocean. Juvenile toothfish are predominantly piscivorous, principally feeding on demersal or benthopelagic fish. The diet differed between South Georgia and Shag Rocks. On the Shag Rocks shelf, which is the main area of toothfish recruitment, the dominant prey is the demersal yellowfin notothen (Patagonotothen guntheri), whilst at South Georgia the main prey were other notothenid fish. The difference in prey composition reflects differences in ichthyofauna between the two areas. The size of prey increased with size of predator, with two cohorts of toothfish taking two distinct cohorts of P. guntheri.