Background: Under-five mortality is one of the indicators of the millennium development goals (MDGs) for the child mortality reduction goal. Understanding the social determinants of underfive mortality is helpful to narrow the gap between different social classes. Therefore, this study focused on the social determinants of under-five mortality in Ethiopia using EDHS 2011 data. Methods: The data source for this analysis was the 2011 EDHS which was undertaken over a five-month period from 27 December, 2010 to 3 June, 2011. The sample was selected using a stratified, two-stage cluster design. Samples of 16,515 women of reproductive age were interviewed. The questionnaire used to collect information from these women who had among other things such as background characteristics of women, birth history of these women and the survival of each birth at the time of the interview. Births that had occurred to women in the last 10 years prior to the date of the interview were extracted for the analysis. Descriptive statistical methods were used to describe the distribution of the characteristics of the data. Kaplan Meier plots and incidence rates per 1000 person years were used to compare survival across different categories of the risk factors. The effect of the risk factors on survival was analyzed using Cox proportional hazards regression. Data management and analysis were carried out using STATA 10. Results: A total of 23,581 under-five children were included in the study. The under-five mortality incidence rate in Ethiopia for the last ten years was 29.6 per 1000 person years. Maternal education beyond primary level of education reduced the risk of under-five mortality by about half. A significant reduction in risk of under-five mortality was observed among births to mothers residing in richest households. The hazard ratio (HR) was higher for under-five mortality among boys than daughters, twins than singleton, teen age mother than higher ages and short births than optimal. Conclusions: Empowering mothers with education and making them productive for improving their income are important aspects for reducing under-five mortality. Emerging regions were disadvantaged on the incidence of under-five mortality; however, there was a positive result in narrowing the urbanrural under-five mortality risks. Being teenage mother at birth, short birth interval and twin births were identified risk factors for increased under-five mortality in Ethiopia. Interventions targeted at empowering women and much effort in emerging regions are required. Preventing teenage motherhood and promoting optimal birth spacing are also required to reduce under-five mortality in Ethiopia.