This research was conducted to investigate the development situation in South Sudan. The key problem of this study is that why economic development did not occur in 2005-2015? While significant bilateral and multilateral developmental assistance have been donated to the region since the signing of Comprehensive Peace Agreement (CPA) in 2005; in addition to other financial resources from oil revenues. The basic objective of the study is to highlight the major economic, financial, and technical constraints to economic development in South Sudan in 2005-2015. The study has relied on combine methodology that comprises from quantitative and qualitative methods in data collection and analysis. The logic behind this combined methodology is to minimize various defects of each method in data analysis. Different techniques have been used in data collection, among them close-ended questionnaire, focus group discussion, and semi-structured interview technique. In data analysis, descriptive statistics particularly the Statistical Package for Social Science (SPSS) have been used to obtain logical and precise conclusions. The most important results that have been reached by this study are that underdevelopment of South Sudan is attributed to lack of scientific, technical and innovative researching; poor infrastructure; underdeveloped financial sector, absence of planning authority; too much dependency on oil revenues; inadequate investment in basic infrastructure; and lack of access to land. And the main recommendations of the study are that financial and economic resources shall be diversified; scientific researching shall be given much consideration; infrastructure with high quality shall be developed by the Government to promote sustainable development in South Sudan.

Keywords : Low Per Capita Productivity: Income Inequality: Poor Infrastructure.