With the main objective to assess the financial intermediation roles of Ethiopian commercial Banks in promoting economic growth, the researcher has reviewed pertinent literatures and conceptualized the research and adapted the concept of financial intermediation. Accordingly, an appropriate model has been specified to predict economic growth from commercial Banksâ€™ deposit, commercial Banksâ€™ credit to private sector, broad money, investment, minimum deposit interest rate and average lending interest rate along the sample period of the last thirty years (1991-2020). Secondary data from various sources have been collected to analyze and evaluate the role of the Ethiopian commercial banks using STATA. F-statistics, R2, and adjusted R2 revealed that the regression model is robust enough to predict the dependent variable. Moreover, Augmented Dickey Fuller and Durbin-Watson Statistic tests indicated that the variables are stationery at zero degree level. The output of the multiple time series regression model revealed that financial intermediation roles of Ethiopian commercial banks in promoting economic growth had a mixed result. Ethiopian commercial banks deposit, credit to private sector, and broad money had a positive contribution although the co-efficient are statistically insignificant along the sample period. Minimum deposit interest rate had also a positive contribution. However, investment and lending interest rate had been found to be adversely but weakly affecting economic growth highlighting for further studies as to the prevalence of such relationship. Finally, in lieu of the findings, the importance of enhancing deposit mobilization through designing appropriate strategies both at national and bank level and enhancing prudent lending to improve financial intermediation roles of the banks have been recommended to further strengthen the Ethiopian commercial banksâ€™ role of promoting economic growth in the country.