Empirical evidence on the impacts of household poverty and other socio-demographic factors regarding child undernutrition is essential in targeting resourcesMultivariate analyses showed that living in urban of Tigray and Somali regions, poor household wealth status and lack of toilet facility were the urban determinants of child underweight in Ethiopia, whereas living in rural of Gambela and Harari regions, child age of 2 and over, mother's age at first birth being 18 and under, poor and medium household wealth status and child did not take drugs for intestinal parasites in the last six months were factors independently associated with child underweight in the rural of Ethiopia. In conclusion, the study highlighted that special attention needs to be given to policies aimed at reducing underweight based on the magnitude and nature of factors, such as poverty, early marriage, child age, antihelmentic drugs, toilet facilities and regional characteristics.