Now days, banks all over the world are changing their traditional or window based service to branchless. Ethiopian banks are also introducing different E-banking products but it is at infancy level and cash is still the dominant medium of exchange. Mobile banking is one type of E-banking product which is used to make financial transactions. But customers of Commercial Bank of Ethiopia are not satisfied with it. So understanding its success factors of is important for both customers and the bank itself. In this research, the researcher extended the Delone and McLean IS success model to the mobile banking by adding self-efficacy and trust as a success variable. This study aims to analyze the relationship between system quality, information quality, service quality, trust and self-efficacy to user satisfaction and use. In addition, the study aims to analyze the relationship between user satisfaction and use to a net impact. The model was tested by using partial least square structural equation modeling approach. It is both quantitative and qualitative study that was conducted in the form of a survey of 286 mobile banking users of Commercial Bank of Ethiopia and interview questions for some employees of Commercial Bank of Ethiopia. Both purposive and convenience sampling were applied to select bank branches and respondents respectively. Both SPSS V.20 and Smart PLS V2.0M3 were applied to analyze the demographic data and test the proposed model respectively. The findings revealed that information quality, system quality, self-efficacy has positive and significant effect on system use and user satisfaction. And service quality and trust have positive and significant effect on user satisfaction but negative and insignificant effect on system use. Finally, user satisfaction and system use have positive and significant effect on net impact. Based on the finding and conclusion, the study recommended that the bank should work on information quality, system quality and service quality of mobile banking to increase the usage of mobile banking service and its customer satisfaction. Beside this, the Bank should build its customer trust on mobile banking so as to boost its customer satisfaction and mobile banking usage.