Back ground: - The burden of communicable diseases within developing countries is mainlyrninfluenced by poor personal hygiene practices and inadequate sanitary conditions that affectrnhealth of school children. Hand washing with soap (HWWS) is simple and cost effectivernmeasure to prevent transmission of many communicable diseases in school-age children.rnDespite substantial evidence about the effectiveness of hand washing, especially using soaprnat all critical time, the practice is poor in developing countries including Ethiopia. Thernproblem is not researched well on children who are major risk groups for diarrheal diseases,rnARI and other hygiene related problems. This school based cross sectional study focused onrndescribing KAP of school children provides base line information on the area.rnObjective: - To assess knowledge, attitude and practice of hand washing and associatedrnfactors among primary school children in Hosanna town, SNNPR, Ethiopia.rnMethods: - Institution based cross sectional study was conducted in sample size of 246rnstudents in Girma Bekele primary school in Hosanna town from April 15 -30/2016.Data wasrncollected using interviewer administered pre tasted structured questionnaires by trained datarncollectors.rnResult: - From students participated in this study over all 167(69.9%) students have good andrn72 (30.1%) have poor knowledge. Knowledge of students in this primary school is affectedrnby grade of student and area of residence with (AOR, 95% CI 9.099(.587-.850) andrn(AOR.384; 95% CI (.114-.299)) respectively. Regarding the attitude of students 142(59.4%)rnand 97(40.6%) have good and poor attitude respectively. Overall 172(71.97%) of studentsrnhave good practice and 67 (28.03%) have poor practice toward hand washing.rnConclusion:-Majority of the study subjects has adequate knowledge and about more thanrnhalf of them have positive attitude. Overall practice of HW is good but utilization of soap andrnHW after toilet visit is low. Maternal educational status, area of residence, age, sex and gradernof student are factors that affect KAP of school children toward hand washing with soap.rnRecommendations:-The area should have to be further researched to identify where the gaprnis like food handlers condition at home, interpersonal contacts, school environment andrnplaying area and materials and any launches conditions near the school; because irrespectivernof good knowledge level of student the prevalence of diarrhea is still high and hand washingrnafter toilet visit and soap utilization of students is still low.rnKey words: primary school children, hand washing, knowledge, attitude and practice.