Seasonal composition and sexual differences in the diet of the White-faced Ibis (Plegadis chihi) were investigated in Buenos Aires Province, Argentina. A total of 88 stomach contents were analyzed, from White-faced Ibis feeding on riparian pastures and grasslands in the Magdalena district, Buenos Aires Province, Argentina. Samples were obtained between 1992 and 1996, covering each season of the year. The trophic spectrum was determined based on the identification of 59 items, mainly belonging to animal taxa. Diet was composed of Insecta (43 items), Arachnida (3 items), Crustacea (5 items), Gastropoda (3 items), Hirudinea (3 items), Amphibia (1 item) and vegetable (1 item). Dietary composition was analyzed in terms of number, frequency of occurrence and volume, for each season and between sexes. Significant differences between sexes were found in the volume of the ingestion consumed.