The purpose of I his study was lo investigate the level of instructional leadership' practice using instructional function in effective and in-effective primary school principals of Gidan woreda, Amhara Region and their sigr1/fi<'ar1ce difforence. Comparative research ofquamitative research method was employed and followed qualitative research lo triangulate the data if' ii was necessary. F.ig/11 schools lF<:re selected (JS 11 . ..,·01n[.JI£~ usirig purposive techniques: 11() teachers, r'? principals and 8 internal supervisors wete selected from sample schools using proportional stratified random sampling for teachers and comprehensive sampling for principals and sup!rvisors both sample schools. Ouestionnaires for teachers and interview for principals mu/ supervisors 1r<•re th» 111t1i11 instruments used lo gulher dota. Qiu~sfi(>nnairc h·t1s closetl typ« questions whereas interviews n:c.>re semi structured: '/11e reliobilti» ~if ouestionnaire i11 t. .. ach instructional function variables were calculated using cronbach alpha of the pilot test questions. A.:c .... dinglv. the rel~1bility coefficien! for each variable was found. The cumulative calculated coefficient wt:I.>' 0.801. The data which collectedfrom teachers were analyzed by stattstlcat tools which \J.~ere one sampta t-test and independem t-tcst. In addition qualitative data h~ere analyzed the data gathered via interview presented in words. The majorfinding of the study revealed thas al both school in-effective and effective school, principals were performed at the level ofusuallv i11 e_lji/t'I ive schools and somet i111~s in in-effective schools in part icular and instruct ional leadership practice were performed al high level in clfi1cli.vc primary school principals rather than principals who lead in-effective schools. Hence, there is great stotisitcal significance difference between w1 effoctiv« and in-effective primary school principal 011 the instructional leadership' practice of Gidan Worcda. Amhara Region whicl: meun, instructionat leadership .. were practiced at higli level i11 an e.Oeclii•o· primo1y schools than i11bf/ectii·e primary schools of Gidan woreda so as confirmed that high performance schools were the product of principals instructional leadership practices al high level and inejfi'cti••e primary schools n·cr" fire product cl instructional leadership practices al low leve! ABSTRACT x