The summer diet of the Patagonian opossum Lestodelphys halli was studied in southern Argentinean Patagonia. Faeces of opossums captured alive and stomach contents from dead animals were collected and analyzed. A wide variety of invertebrates (87.2% frequency of occurrence) followed by birds and reptiles (10.64%) occurred both in faeces and stomachs, and fruits were occasionally consumed. Although the Patagonian opossum was reported as a carnivorous species in captivity, feeding mainly on rodents, reptiles, birds and invertebrates, we did not find remains of rodents in the diet of the opossums. We suggest that Patagonian opossums are not an efficient rodent predator in the wild. The high consumption of invertebrates, reptiles, birds and fruits during the warm season when these items are abundant reflects the opportunistic behavior of this species.