Medicinal plants in Church Based Forests study was conducted between October 2013 and April 2014, in Tahtary Koraro Wereda, NorthwesternTigray, Ethiopia. The study employed ethnobotanical methods including semi-structured interviews, field observations, preference ranking, paired comparisons and informant consensus. A total of 64 informants from 8 Kebeles (8 informants from each Kebele) were selected purposively and 28 key informants with the help of local administrators, recommendations from elders, and members of the local community. In this study, 102 medicinal plants were collected and identified. These species represent 93 genera and 53 families. The family Fabaceae with 10 species (9.8%), Solanaceae and Euphorbiaceae with 8 species (7.9%) and 5 speices (4.9) respectively were commonly used medicinal plants in the study area. From the total of 102 medicinal plants, 79 species (77.5%) were used to treat human ailments for 44 health problems, 15species (14.7%) were used to 16 livestock health problems and the remaining 8 species (7.8%) were used to treat both humans and livestock diseases. Shrubs are the most used plants, accounting for 38 species (37.22%), herbs 23 species (22.55%) and trees 34 species (33.33%). Leaves, roots, and seeds are the most used plant parts accounting for 54 species (39.7%), 33 species (24.35%) and 8 species (5.9%) respectively. Fresh plant parts from 83 species (65.4%) are frequently used in the study area than dried plant materials (32 species, 25.1%) and both dry and fresh materials (12 species, 9.5 %). From the collected traditional medicinal plants informants reported that a species used as crushed preparations were 63 (46.3%) followed by pounded which were 17 (12.5%) and those used as fumigants were 15 (11%). Most herbal preparations are administered externally compared to internal applications accounting for 51.6% and 48.4% respectively. Key words; ethnobotany, local peole, medicinal plant, aliment, indigenous knowledge, treatment.