A cross-sectional study was conducted to determine the prevalence, intensity, and species of gastrointestinal helminths of free-range chickens in Mashhad, Northeast of Iran. From December 2011 to August 2012, one hundred free range chickens were collected from different regions of Mashhad in Northeast of Iran and gastrointestinal tracts were inspected for adult helminths. Seventy-two percent of the chickens were found as infected with gastrointestinal helminths. Species and prevalence of the helminths were as follows: Ascaridia galli (29%), Heterakis gallinarum (23%), Heterakis isolonche (9%), Subulura brumpti (3%), Raillietina tetragona (15%), R. echinobothrida (11%), and Choanotaenia infundibulum (4%). No trematodes were found. Sixty four percent of chickens had multiple infections while 22% were suffering from single infections. As far as prevalence and mean intensity of infections were concerned, there was no difference between male and female birds. These results confirm the high risk of helminth infections in free range systems and may explain one of the causes of high mortality in them.

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