This research was conducted in Olenkomi district west Shewa, western Ethiopia. The aim of the study was to organize and document information on use, management and conservation of medicinal plants by Olenkomi woreda .The study involved traditional healers, knowledgeable elders, local elders and local communities. Different Ethnobotanical techniques were used to collect and analyze data generated by semi structured interview.Gguided field walk; observation and group discussion were conducted. Preference ranking, paired comparison, direct matrix and fidelity level index combined with descriptive statistical analysis were performed. One hundred ten (110) informants were involved from eleven kebeles. A total of eighty one (81) plant species 37 from wild, 24 from home garden and 20 plant species from both wild and home garden. Among 81 collected medicinal plant species 45(55.55%) plant species are used to treat human ailments, 13(16.04%) are used to treat livestock ailments and the rest 23(28%) are used to treat both human and livestock ailment. Herbs were the dominant with 32(39.5%) followed by trees 19(23.45%) then 18(14.81%) species were climber.Leaf was the most frequently used part medicinal plants. The plant species that are collected from the district in addition to their medicinal value also used for food, spices, furniture, fencing, construction and charcoal. The highest informant consensus was documented to the plant Lepidium sativum cited by 55 informants for its medicinal value treating abdominal problem. Rumex nepalensis, Ajuga integrifolia and Anetum graveolens informants ranking second third and fourth respectively for medicinal value. Oral administration were the dominant route 55.55% followed by dermal 30.30% .Oocular teeth and others are also observed route of administration applied through squeezing, crushing, boiling, chewing, roasting, smoking and fluid juice . Communicating with indigenous people was the dominant knowledge transfer system while others restricted within the family. Group discussion, direct matrix, ranking results indicated that agricultural expansion was the main factor threatening medicinal plants in the study area.