Background: Low birth weight is closely associated with fetal and neonatal morbidity, inhibitedrngrowth and cognitive development, and chronic diseases in life. Birth weight also predicts thernchildâ€™s future health, growth, psychosocial development, and survival. Low birth weight can berndefined as weight at birth less than 2,500 grams irrespective of gestational age. In developingrncountries, a birth weight below 2,500 grams is the leading cause of infant and child mortality andrncontributes to several poor health outcomes. In Ethiopia, the prevalence of LBW is as high asrnmore than 13% according to studies from different regions of the country. Birth weight is a goodrnsummary measure of multifaceted public health problems that include long-term maternalrnmalnutrition, ill health, and poor health care during pregnancy. rnObjectives: Main aim of this study is to identify determinant factors of low birth weight amongrnnewborns delivered in Addis Ababa public hospitals 2018/2019. rnMethods: A hospital based unmatched case control study will be conducted among 279 deliveriesrnfrom March to April 1 2019 in Addis Ababa public hospitals, Ethiopia. The sample size isrndetermined using double population proportion formula N=279. Consecutive sampling techniquernwill be used to get cases and systematic sampling to get controls. Data will be collected byrninterviewing the mothers, reviewing medical records and measuring the anthropometry of thernmothers and the newborns using structured and pretested questionnaire. Data will be entered usingrnEpi-data 4.12 software and analysis will be done using SPSS 23. Variables that show significantrnassociation in the bivariate logistic regression analysis (p