Diets for captive amphibians are often inadequate and lead to poor health. To determine the natural diet of two New Zealand frog species, we analysed the stomach contents of 16 Archey's frogs (Leiopelma archeyi) from the Moehau Range of the Coromandel Peninsula and nine Hochstetter's frogs (Leiopelma hochstetteri) from the Moehau Range of the Coromandel Peninsula, the Hunua Ranges and Maungatautari. These specimens were obtained as by-catch from invertebrate pitfall traps from 2002 to 2008. Both species ate a wide range of invertebrates including springtails, mites, ants, parasitic wasps, amphipods and isopods. Leiopelma archeyi also ate snails. The mean ratio of maximum prey size ingested to snoutÁvent length in L. archeyi was 0.31 (range 0.16Á0.5), and in L. hochstetteri was 0.42 (range 0.21Á0.75). We suggest a reformulated captive diet based on the species and size of invertebrates ingested in the wild. This diet may assist in the prevention of metabolic bone disease.