This study involved clinicpathological comparison of natural chronic and acute forms of orf virus infection which took place in a flock of sheep. Clinically, lesions in the acute orf took 5-6 weeks to heal, while healing in the chronic form took more than six months. Significant differences were observed on the histopathological lesions of both forms of the disease. Grossly, the scabs on the acute disease could be removed easily. How- ever, in the chronic form they were strongly adherent to the skin and when forcibly removed they caused bleeding. Comparative discussion of both conditions was undertaken.