The diet of the Great Pampa-finch includes seeds rather than insects. Our objective was to study its diet during the winter season and, whenever possible, to record differences between the sexes in diet patterns. This species was studied at Guamini Lagoon, Buenos Aires Province, Argentina. The stomach content of 38 adult birds was investigated. The analysis shows that the food eaten by E. platensis consisted of seeds (60%) (Chenopodiaceae, Asteraceae, Ciperaceae and Poaceae) and insects (39%) (Bellostomatidae, Dytiscidae, Curculionidae, Coccinelidae, Formicidae and Apidae). Males ate more insects and, overall, more items than females. These, in turn, consumed a greater amount of plants. Niche breadth values were 2.9 for males and 3.1 for females. The seeds encountered were those of plant species typically associated with the pampas.