In order to identify nematodes related to oak trees of Khoramabad County 82 samples were collected from rhizosphere and bark of oak trees of Khoramabad County different regions, during 2014 and 2015. After extraction, killing and fixation of nematodes transferred to glycerin according to the modified De Grisse method (1969), identification of specieses based on morphological and morphometrical characters was performed using the light microscope, equipped with digital, camera. In the study, 26 species Amplimerlinius globigerus, Aphelenchus avenae, Aprutides guidetti, Boleodorus thylactus, Discotylenchus sp., Ditylenchus anchilisposomus, Ditylenchus medicaginis, Ditylenchus parvus, Helicotylenchus digonicus, Helicotylenchus exallus, Helicotylenchus vulgaris, Laimaphelenchus australis, Laimaphelenchus penardi, Merlinius brevidens, Merlinius nanus, Mesocriconema antipolitanum, Paraphelenchus amblyurus, Paratylenchus similis, Pratylenchoides ritteri, Pratylenchus neglectus, Pratylenchus thornei, Psilenchus hilarulus, Scutylenchus rugosus, Trophurus ussuriensis, Xiphinema index, Zygotylenchus guevaraiof the infraorder Tylenchomorpha and the family Longidoridae were identified. Among the identified nematodes, species 19 are reported from oak trees rhizosphere in Iran for the first time. spesieses of Laimaphelenchus australis with 360-486 μm body length, 4 incisures at lateral fields, 9.8-10.8 μm length of stylet, Vulva without anterior flap, Post vulval uterine sac 23.3-32.2 μm long, Tail conoid, ventrally curved, with 4 finger-like protrusions at ending, 22.7 μm length of spicule. And the males of L. penardi with 25–26 μm length of spicule, 13 μm length of stylet, caudal papillae located at three positions: first pair before anus and second and third pair after anus, these two species are new records for Iranian nematofauna and were collected from oak trees cortex in Khoramabad County