This paper examines External Debts Management Strategies in developing economies and its implications on some key economic indices using Nigeria as a case study. This work has adopted both the content analysis and the empirical approach. Data for this study were basically secondary data. The quantitative data for analysis were gathered from the statistical bulletins/releases of relevant government agencies like the Debt Management Office, Central Bank and the Office of the Accountant General of the Federation. The qualitative information was sourced via textbooks, and scholarly journal publications accessed through the internet. Data were analysed using the Linear Regression and Analysis of Variance (ANOVA). The linear regression showed that there is a positive and significant relationship between the size of External Debts and Gross Domestic Product (GDP), Capital Expenditure, External Reserves and Exports. However, the Analysis of Variance (ANOVA) reveals a negative correlation between External Debts and the variables studied. The study attributes this anomaly to mismanagement of credit facilities, unfavourable loan terms characterized by capitalization/compounding of interests, weak economic base, poorly co-ordinated statistics on loans and overdependence on foreign aids among others. This development has led to poor performance of almost all the key economic indices of the country resulting in dearth of infrastructural development, very weak real sector, and high unemployment rate and so on. The paper recommends that developing economies should manage credits better by appropriating the funds to sectors that would ensure diversification of their economic base. Nigeria should pursue deliberate policy that will encourage a virile productive sector, place less emphasis on external borrowings as most of the credits are given under very unfavourable credit conditions and their repayments erode the much needed funds for economic development. The various governments should see external borrowings as a last resort and when contracted must be employed to finance only self- sustaining projects that will stimulate real sector and other factors of production needed to engender sustainable economic development.