Elegant Crested-Tinamou is omnivorous, although during most of the year it primarily feeds on seeds, fruits, and leaves. A wide range of plant species are consumed; among the more frequent are ears and grains of Bromus and Hordeum, also fruits of Erodium cicutarium, Lycium chilense and Condalia microhylla (Bohl 1970). Invertebrates are consumed throughout the year, but more frequently in the summer; insects taken include the grasshoppers Trimeratropis pallidipennis, Dichroplus pratensis, Dichroplus elongatus, Scyllina variablis and Scyllina signatipennis (Bohl 1970). Crops of these tinamous also sometimes contain small stones and sand, although "only a small amount of grit appears in their crops" (Bohl 1970).
Kufner (1997) studied the diet of Elegant Crested-Tinamou in the Monte desert, Argentina and its seasonal changes were evaluated. The annual diet consists mainly on dicotiledoneae and formicids. Different types of food item vary seasonally during autumn-winter, possibly related with breeding season and development requirements. Diet diversity presents lower values in spring and higher in autumn, during drought.