The two marsupial moles are the sole extant members of the order Notoryctemorphia, an ancient Australian lineage, with extreme adaptations for fossoriality. We tested whether the order conforms to the expectation that the low productivity of subterranean environments results in subterranean mammals being generalist feeders. To do this, we examined diet, invertebrate availability in foraging areas and prey selection by the southern marsupial mole or Itjaritjari Notoryctes typhlops, which occupies the sand deserts of southern and central Australia. Because the species is so infrequently encountered, we examined digestive tracts from museum specimens which themselves are rare; we obtained access to ∼12% of all specimens available in Australia's museums. Our invertebrate sampling protocol was based on a novel survey method, which, for the first time, enables quantification of the distribution and habitat use of N. typhlops. We sampled topographic positions on sandridges and areas of the soil profile (0–70 cm) where marsupial moles forage. Rarefaction methods indicated our sample size was sufficient to record the majority of prey items. Material in digestive tracts of 16 specimens consisted of five insect orders (Coleoptera, Hymenoptera, Isoptera, Lepidoptera and Orthoptera), scorpions, spiders and plant material. N. typhlops consumed two main prey types: social insects (ants and termites) and the larvae of beetles. Ants, termites and beetle larvae were also the main invertebrates captured in soil cores on sandridges; other invertebrates combined contributed <5% to abundance. Prey selection assessment using Jacobs' index and Bonferroni confidence intervals indicated an active avoidance of termites (D = −0.61), whereas ants (D = −0.13) and beetle larvae (D = 0.57) and all other prey categories were taken in proportion to availability. Our results show that N. typhlops is best classed as a dietary generalist despite its specialized adaptations for a subterranean lifestyle.