Background: Traditional knowledge on the use of medicinal plants is in danger of extinction because of different changes taking place all over the world including Ethiopia and thus there is a need for its immediate documentation for the purpose of conservation, sustainable utilization and development. Thus, an ethnobotanical study was conducted in Ambo District, Oromia Regional State of Ethiopia to document and analyze local knowledge on medicinal plants used for the treatment of animal diseases.Methods: Data were collected between November, 2017 and April, 2018 mainly through semi-interviews conducted with purposively selected informants. Data collected mainly included demographic information of respondents, local names of medicinal plants, plant parts used, preparation methods, mode of applications, diseases treated, and habit and habitat of the reported plants. Based on data obtained through interviews, Informant Consensus Factor (ICF) values were computed.Results: A total of 55 medicinal plants used to manage livestock ailment were reported by informants in the Ambo District. Herbs were commonly used in the preparation of remedies. Leaf was the most frequently utilized plant part accounting for 49.1% of the total reported medicinal plants. The majority (69.0%) of the medicinal plants used in the study District were uncultivated ones mainly harvested from edges of forests and bushlands, roadsides, river banks and grasslands. High ICF values were obtained for ophthalmological (0.82), dermatological (0.79), febrile (0.77) and gastro-intestinal ailments (0.77).Conclusion: The current study shows that there is still rich traditional knowledge on the use of plants to control various animal diseases in study District. However, such claim needs to be scientifically verified with priority given to medicinal plants used in the treatment of ailment categories with high ICF values as such plants are considered to be good candidates for further pharmacological evaluation.