The paper analyses the functioning of Teff and Maize marketing system in southern Ethiopia. The methodology follows the industrial organization paradigm: structure, conduct and performance(S - C-P). The results reveal high market concentration, high barriers to entry in terms of capital and credit, evidence of collusion in the rural market, concentration, high barriers to entry in terms of capital and credit evidence of collusion in the rural market, low market integration, high marketing margin, and high seasonal price variation which indicate the inefficiency of the Maize and Teff marketing system. There are basic constraints such as poor market infrastructure and lack of capital, credit and clear property right law to increase private investment in the food grain marketing sub-sector. In spite of the complex problems after the March 1990 reform, the Maize and Teff marketing system appears to be improving and working better by market structure standard