The eastern woodrat, a state-endangered species, is a generalist herbivore that depends on cached food during part of the year. We identified seasonal variation in the diet of woodrats at Pine Hills, Union County, Illinois, based on analysis of fecal pellets, and determined if they consumed forage in proportion to its availability in the habitat. Woodrats did not consume forage in proportion to availability for any season during 1995. Mast, primarily hickory nuts, comprised 61-67% of the diet each season, despite no mast available in the habitat during spring, and relatively little during summer. Few herbaceous species were eaten during any season; only Virginia creeper was identified in fecal samples throughout the year. Virginia creeper, spicebush, and sedge accounted for 79.4% of the identified herbaceous material consumed throughout the year, despite relatively low availability in the habitat. Resource caching decisions of woodrats depend on nutrient content and perishability. Woodrats appeared to ration cached resources so as not to be left with poor foods at the end of the cache-dependent period.