They consume a variety of foods but most commonly the seeds of grasses and forbs, green vegetation, and dry vegetation. They occasionally consume animal material, mostly arthropods. Harvested seeds are transported in cheek pouches to burrows and consumed or cached there. Ord's kangaroo rats are easily able to retrieve shallowly buried seeds. Kangaroo rats are physiologically adapted to arid environments.
Most water is obtained from seeds and succulent plants.
Seed predation and soil disturbance are the major influences of Dipodomys species. They exhibit a preference for large seeds and their soil disturbance promotes annuals over perennials. In southeastern Arizona desert scrub, removal of the three Dipodomys species including Ord's kangaroo rat resulted in a shift from shrubland to grassland.