Although Brazil has a great bird diversity, information on the health status of free living psittacine is scarce. The aim of this study was to determine the prevalence of endoparasites and the ratio of gram-negative versus gram-positive bacteria in the feces of free-living adult Hyacinth and Green-winged macaws. Fecal samples were collected placing camouflaged sheet covers on bird foraging areas. Fifty-five swabs were evaluated by gram staining technique and 101 fecal samples were analyzed using flotation and centrifugation methods. None of the samples presented parasites or ova. The presence of gram-negative bacteria was detected in 1.8% of the fecal samples. These results suggest that parasites and gram-negative bacteria may be transient in the gastrointestinal tract of healthy free-living psittacine birds. This situation is quite different from what is observed for birds in captivity, where stressful events and improper husbandry facilitate the dysbiosis and high parasite loads, with an imbalance in the host-parasite relationship.