Botanical composition of the diet of White-tipped Plantcutter Phytotoma rutila in the central Monte desert from Argentina, was determined by microhistological analysis of excreta. In both sexes, the diet was composed by a high proportion of fruits (26.8%) and leaves (35.6%) from the shrub Lycium tenuispinosum (Solanaceae) and leaves from the tree Prosopis flexuosa (Fabaceae) (26.8%). P rutila is a predominantly folivorous bird with a high consumption of fruit during summer, when these items are abundant, which shows an opportunistic behavior.