Malnutrition is a broad term that refers to all forms of poor nutrition caused by a complex array of factors. Proper nutrition is essential for healthy and active lives, well-being, and has direct bearing on intellectual capacity, which eventually impacts positively on social and economic development.To understand the determinants of malnutrition under-five children,a study was conducted in Gede'o Zone,Southern Ethiopia.The result of this study illustrated major determinants of Child malnutrition;household socioeconomic and behavioral characteristics such as poor child feeding practice at earlier age resulted from Household economic downturn,Geo-economic tiresome of land asset and wage earnings, inadequate income for livelihood and socioeconomic status of women, soaring food item prices.An institutional faults; meager household development support for self-reliance,limited inter-sectoral collaboration in nutritional mainstreaming have found determinants for child malnutrition. Itis recommended therefore, an integrated holistic approach that involving various sectors and sub-sectors to foster nutrition friendly development schema.