Short-beaked echidnas (Tachyglossus aculeatus) are myrmecophages, or ant and termite insectivore specialists, and replicating their exact diet in captivity is problematic. Diets for captive animals often incorporate raw meat, eggs and cat food mixed together with water, and vitamin and mineral supplements. These diets have promoted a number of health problems in captive echidnas, such as gastritis, cystitis, gut impaction, obesity, and diarrhea. A manufactured diet was designed and three echidnas from two zoos were transitioned onto this diet to assess the acceptability and digestibility of this diet for echidnas. The new "test" diet was readily accepted by the echidnas with a 1 week transition period. Daily digestible energy intake was 280 kJ kg d , similar to another myrmecophagous species. Digestibility values were above 74% for all macronutrients. It was determined that this diet was an acceptable replacement for the previous diets and it was decided that the remaining echidnas at both institutions would be transitioned to the new diet. The diet will also be used for wild echidnas being rehabilitated in the zoo hospitals prior to release and commercially available within Australia. Further data are being collected to assess the use of this diet for seasonal weight management, transitioning hand-reared puggles and effects on gastrointestinal tract health. Zoo Biol. 36:56-61, 2017. © 2017 Wiley Periodicals, Inc.