The aim of study was to necropsy and histopathology evaluation of lung Crenosoma striatum in hedgehog. In July 2012, 10 porcupines were collected from Urmia city and transferred to parasitology lab of the veterinary faculty where they were euthanized by ketamine (over 40-90 mg/kg) intraperitoneally. In this study the lungs were assessed through naked eyes regarding parasite presence upon washing. The lung tissue was examined under loop microscope in order to finding small worms in lung parenchyma. The worms were removed by Anse forceps and kept in AFA solution, and collected for diagnosis. In order to carrying out pathological tests, some samples prepared and placed in formalin 10 % for fixation. The counted worms frequency in high severe and moderate lungs were as 86 (50 females and 36 males) and 19 (13 females and 16 males) worms respectively. But no worms were observed in healthy lungs. The infestation severity was as; low infestation (1-7 worms), moderate infestation (8-20), severe infestation (21-50) and very severe infestation (more than 50 worms). The lung examinations of non-infested lungs indicated that the lung tissues had no parasite. In addition, no inflammation reactions as inflammatory cells presence were observed, and the air spaces with alveoles' wall in some regions were observable. On histopathological examination, the observed alteration was primarily inflammatory changes, and in some cases the proliferation was also observable. Hyperemia and inflammatory cell infiltration, somehow the alveolar space was filled, representing bronchopneumonia reaction. The bronchioles had various changes as hypertrophy and hyperplastic in different parts of respiratory system. Hyperemia and hemorrhage were very severe in some cases caused hemosiderosis in the lung. In severe inflammations the pneumonia along with increasing of bronchial cells in the lumen rose as well, leading to severe verminous infestation of the lung. In regard to the obtained results, the verminous infestation of the porcupines' lung with C. striatum indicated inflammatory and proliferative alteration which was as inflammatory changes in mild cases, and inflammatory and proliferative stances in severe cases.