Nutrition is the intake of food, considered in relation to the body’s dietary needs. Good nutrition – an adequate, well balanced diet combined with regular physical activity – is a cornerstone of good health. Poor nutrition can lead to reduced immunity, increased susceptibility to disease, impaired physical and mental development, and reduced productivity. The aim of this study was to analyze the determinants of Stunting and Wasting among Under-five Children of Segen Area People and South Omo Zone, Ethiopia. A total of 339 children are selected from 5 woreda using self-administered questionnaire. From these 148 children are females and 191 are males and 35.4% of children are wasted and 54.9% are stunted. Binary logistic regression model was used to analyze the data. Among the various socio-economic, demographic and child health and care practices characteristics considered, residence, Primary mothers education level, sex of the child (female) are significantly associated with wasting. Rural residence, mothers’ education level and female child were remained to be significantly associated with stunting. The prevalence rate of malnutrition in the study area was found high and this was coupled with association of many independent variables. Family religion, mothers’ occupation, mothers education level, family food source, source of drinking water (public tap), child sex, child order, duration of breast feeding, vaccination status, prenatal and postnatal care, Diharrea and Fever are associated with wasting and stunting.