Schooi-based practices of teachers' continuous professional development are thernmeans by which teachers and school leaders up-date their professional knowledge,rnskill, and altitudes. It is held that teach e rs should get opportunities to improve th e irrnprofession and produce a productive citizen through providing relevant education forrntheir learners. School-based practices of CPO are more supportive to create accessrnto all teachers and for the whole development of the school. Th e purpose of thisrnthesis was to identity and analysis the school-based practices of teachers'rnprofessional development in the selected senior secondary schools of NorthernrnShowa Oromia Regional State. On the top of this, it was believed that findings of thernstudy would con tribute to the improvement of school-based practices o f teachers 'rnCPO and its management in the sampled schools. A descriptive survey method ofrnresearch was used to study the problem. To do this, four senior secondary schoolsrnwere take n as a sample using simple random sampling from 15 secondary schools.rnOf these schools teaching (1461 and leading (44) staff members, 88 teaching and 28rnleading staff members were taken as sample population . 77 teaching and 27 lea din grnstaff members responded the questionnaire. 36 students, 12 communityrnrepresentatives, 15 wordage needful cation office expert s were in interviewed.rnBased on their information interpretation and analysis was taking place .rnThe findings of the study sh owed tha t school- base d practices of teachers CPO werernat low stage . Its activity was below the expected level. Because there was no anyrnresponsible body reacted in planning , programming and organizing the CPOrnpractices in the senior secondary schools as we ll as on the top education sector, thernsuccess was in adequate. Some focused practices were practices such as classrnobservation , staff meeting for discussion , ELiP and personalize dings . But the primernCPO practices such as action research on education, mentoring and induction forrnthe NQT were not well developed in the selected senior secondary schools ofrnNorthernshows zone of Oromia Regional State .