Although the fungal diet of Australian mammals, including macropodids (kangaroos and wallabies), is reasonably well understood, no work has been done on mycophagy among New Guinea mammals. We examined stomach samples from the black forest wallaby, 'Dorcopsis atrata' (one sample), greater forest wallaby, 'Dorcopsis hageni' (two samples), lesser forest wallaby, 'Dorcopsulus vanheurni' (five samples), and the dusky pademelon, 'Thylogale brunii' (one sample), for the presence of spores of epigeous (mushroom-like) and hypogeous (truffle-like) macrofungi. All wallaby species were found to have consumed a range of fungal taxa as part of their diet, including those taxa that form symbiotic relationships with forest trees and produce truffle-like fruit-bodies. This is the first record of truffle consumption of fungi by mammals in New Guinea. Our work suggests that forest wallabies are important dispersers of fungi, and may play a significant role in maintaining mycorrhizal communities and healthy forest ecosystems in New Guinea.