Parasitic nematodes of ovine abomasum have economic and hygienic importance throughout the world and Iran. This study was aimed to evaluate molecular identity and species diversity of parasitic nematodes in the abomasum of slaughtered sheep in Ilam city, west of Iran. In this study, a total number of 240 of abomasa were randomly collected from the slaughtered sheep at industrial slaughterhouses in Ilam city at dierent seasons (spring, summer, fall, and winter) between 2017 and 2018. The abomasum content and abomasal mucosa were removed and washed. The collected nematodes were morphologically identied. The genomic DNA was extracted and a 300bp-fragment-length from internal transcribed spacer 2 ribosomal ribonucleic acid (ITS2-rRNA) gene was amplied. Overall prevalence was 66.7% (160/240). Five species of four genera of nematodes including Marshallagia marshalli(43.7%), Ostertagia circumcincta(15.5%), Parabronema skrjabini(5%), M. occidentalis(2.5%),and Haemonchus contortus(0.04%) were identied. Ostertagia circumcincta and H. contortus were found to be dierent in two nucleotides.
