Ovine Progressive Pneumonia is a multisystemic disease caused by Maedi-visna virus in the Lentivirus subfamily in the Retroviridae family. It is aimed to discuss the etiology, epidemiology, transmission types, clinical findings, necropsy findings, preventive medicine and eradication strategies of the disease. Although the disease first appeared in Iceland, it has been reported to occur sporadically in some countries, including Turkey. Maedi-visna virus causes progressive pneumonia (maedi) and meningoencephalomyelitis (visna) in sheep. Virus that infecting cells of monocyte-macrophage origin, causes a multisystemic infection that can affect the lungs, mammary glands, central nervous system, or joints. Chronic weight loss, respiratory distress and exercise intolerance, which can lead to death, are the most common clinical findings in the disease, which mostly affects sheep older than 2 years of age. The most commonly used test for the diagnosis of the agent based on the determination of the specific antibody level is ELISA. In order to prevent the disease, milk or colostrum that causes vertical transmission should be pasteurized; contaminated syringes and milking machines that cause horizontal transmission should be avoided. There is no effective vaccine against the causative agent. As a result, it is necessary to develop an effective eradication program against the maedi-visna virus, which is one of the problems in sheep both in the world and in our country, in order to minimize the damage that the disease will cause to both animal health and the national economy in the future.