A cross-sectional survey on gastrointestinal helminths was conducted on 124 chickens raised under traditional management system in two selected districts namely Adaa and Adamitulu of Eastern Shewa zone, Ethiopia. Of these chickens, 111 (89.5%) were found to harbor one of the five different helminth parasites and 13 (10.48%) were free of helminths parasites. The study also found that 103 (83.0%) and 72 (58.0%) of the examined chickens were invariably infected by diverse species of cestodes and nematodes species, respectively. There was a statistically significant difference (p<0.05) in the prevalence between cestodes and nematodes of helminths parasites within the same district. The major cestode species recovered form chickens were Raillietina echinobothrida 79 (63.7%), Raillietina tetragona 70 (56.5%), Raillietina cesticillus 50 (40.3%) and Choanotaenia infundibulum 17 (13.7%), Davainea proglottina 10 (8.1%), Hymenolepis contaniana 22 (17.7%) and Hymenolepis carioca 7 (17.7%). The major nematode species encountered were Heterakis gallinarum 47 (37.9%), Ascaridia galli 40 (32.0%), Gongylonema ingluvicola 32 (25.8%), Dispharynx nasuta 5 (4.0%), Heterakis isolonche 11 (8.9%), Allodapa suctoria 9 (7.3%), Capillaria anatis 4 (3.2%) and Heterakis dispar 8 (6.5%). The study also tried to see the prevalence of these parasites in relation with age and sex however, it has no significant difference (p>0.05) with those risk factors. On the other hand district significantly affect the prevalence of some parasites (p<0.05). This study strongly suggested that helminthosis is a very serious problem of backyard chickens in eastern Shewa zone of Oromia and appropriate control strategies need to be devised.