Back ground: Diarrheal disease is the most common cause of illness and the second leading cause of child death in the world. The burden is greatest in the developing world including Ethiopia. In Ethiopia diarrhea kills half million under-five children annually secondary to pneumonia. The purpose of this study has been to identify socio-economic, demographic, environmental and behavioral factors that affecting diarrheal morbidity of under-five children in selam kebele south west Ethiopia. Methods: Community-based cross-sectional study was conducted in south west Ethiopia, tepi town selam kebele from March 15– 21, 2017. One hundred three mothers/ care takers of index under-five children living in the households selected randomly by using random number table from the kebele constituted the study population. Data were collected using structured and pre-tested questionnaire. Binary logistic regression model was used to identify the risk factors of diarrheal morbidity for the last two weeks. Results: Prevalence of diarrheal morbidity over a period of two weeks preceding the study was about 18.44%. In chi-square analysis source of water, latrine owner ship, dirty material in right hand finger , Practice of eating unwashed vegetables, and, Personal hygiene of the child, were significantly associated with prevalence of diarrhea among under-five children (P<0.05). However, only Practice of eating unwashed vegetables, is not significant from binary logistic regression among those variable that were significant (P<0.05) in chi-square analysis. Conclusion: As diarrheal morbidity was major problem among under-five children in south west Ethiopia tepi town in the case of selam kebele. Therefore efforts should be invested to generate protected water source and educate parents about the importance of using protected and qualified water source to reduce the exposure children to diarrhea morbidity and mortality.
