The central focus of this work is identifying and analyzing the factors that determine the success and failures of public service delivery in relation to customer satisfaction. Currently civil service reform program is undergoing in Ethiopia. The main element of the reform program is delivering efficient and effective service to the public. In this regard there are some public institutions that are successful in satisfying their customers by implementing the reform program. On the contrary there are others still not successful. Therefore the major public service delivery factors that were suggested by different researchers and scholars are tested using case study method in this work. Two public organizations are selected i.e. one from the category of successful once and the other from those who are not successful based on the previous researches and preliminary assessments. By designing the conceptual framework, the public service delivery success factors are identified scientifically. In addition different approaches and methods of public service delivery reforms are analysed.