Ovine pulmonary adenocarcinoma (OPA) is a contagious and transmissible lung cancer of sheepresembling human bronchiolo-alveolar carcinoma. In the present study, lungs of 9400 sheep slaughtered inFars province, Iran were examined morphopathologically. The OPA was diagnosed in the lungs of 21(0.22%) out of 9400 sheep. Frequency of involvement of different lobes in the affected lungs was includeda...