`Listeriosis' which was hitherto un-known in Pakistan first diagnosed amongst the Buffaloes of Military Farms, Okara, in 1962. Adult and weak buffaloes are more susceptible to the disease. The mode of transmission is not definitely known and according to a month-wise data collected from various farms, the mortality is about 64.5 per cent. Post-mortem examination showed that the animals lost weight rapidly and were in poor condition before death, and their abdominal, thoracic and cranial cavities were found highly affected. Vaccine and chemotherapy against the disease are recommended.