This analysis was to indicate the determinant of Under Five Mortality Rate (U5MR). Data from 130 countries were analysed by applying Multiple Regression Analysis. The source of data was 'The State of The World's Children 1987' by James P Grant, published by UNICEF. The Dependent variable of this analysis was Under Five Mortality, and the Independent variables comprised 4 groups of variable i.e. Education, Nutrition, Health, and Economic. The analysis for each group of variable separately showed that Level of Women Education (Secondary School Enrolment Ratio of Women and Literacy Rate of Women) could explain 69.9% variation of U5MR. None of Nutrion variables could explain variation of U5MR. One variable of Health (Coverage of Polio immunization) could explain 43.1% variation of U5MR. and Gross National Product (Economic variable) could explain 31.8% variation of U5MR. Further analysis of those determinant variables (Level of Women Education, Coverage of Polio Immunization, and GNP) together as independent variables and U5MR as dependent variable showed that GNP could not explain variation of U5MR. The variables (Level of Women Education and Coverage of Polio Immunization) could explain 74,1% variation of U5MR. In general Level of Women Education was the most important determinant for Under Five Mortality Rate variation.