Introduction: The aim of the study was to determine the prevalence of intestinal helminths in red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in the Augustów Primeval Forest (north-eastern Poland), with particular regard to zoonotic parasites.Material and Methods: Intestines from 53 raccoon dogs and 66 red foxes were examined with the use of sedimentation and counting technique (SCT). Samples of faeces from 51 red foxes and 50 raccoon dogs were examined with the use of flotation method.Results: Parasitic helminths were found by SCT in 98.5% of red foxes and 96.2% of raccoon dogs. Both species were infected with: Alaria alata (93.9% and 94.3%, respectively), hookworms (68.2% and 83.0%), Apophallus spp. (7.6% and 15.1%), Mesocestoides spp. (57.6% and 24.5%), Taenia spp. (40.9% and 1.9%), and Toxocara/Toxascaris nematodes (33.3% 15.1%). Echinococcus multilocularis was detected only in red foxes (6.1%), but trematodes Echinostomatidae and nematodes Molineus spp. only in raccoon dogs (18.9% and 41.5%, respectively). Additionally, Capillaria spp. eggs were detected by flotation method in 78.4% of foxes and 20.0% of raccoon dogs.Conclusion: The study showed a very high percentage of red foxes and raccoon dogs infected with intestinal helminths in the Augustów Primeval Forest. Moreover, dangerous zoonotic parasites also were found, which should be taken into consideration in the assessment of infection risk for humans in this region.