It is estimated that about 10.8 million children die each year. Six countries (China, Congo, Ethiopia, India, Nigeria, and Pakistan) account for 50% of worldwide deaths in children under age of 5 years (Black RE, et al 2003; 226¬34). According to Ethiopian Central Statistics Agency, Ethiopian has one of the highest mortality rates in the world among infants and children less than 5 years old (CSA, 2000). The problem that guided this study is that infant and child mortality and morbidity disparities continue to be observed in the areas of improved expansion of the provision of health care services as well as in areas of where poor provision of health care services exist. The key findings of this study points out that factors such as poverty, health care system, diseases, maternal care and family care are the most influential factors that have been responsible observed infant and child under age five years mortality rates disparities between the two regions of Ethiopia in 2005/2006. Factors such as education and access to information seem to be less significant in explaining the observed infant and child mortality rates disparities between the two regions.