The existence of Islamic banking in Indonesia has formally commenced since 1992. But until now, the national Islamic banking has not been able to compete with the conventional banking’s market share position. This study aims to analyze the factors affecting the profitability (ROA) of Islamic banking, including third-party Funds (DPK), Capital Adequacy Ratio (CAR), as well as Financing To Deposit ratio (FDR) as an intervening variable. The population of this study is all of the Islamic banking in Indonesia in the period 2010-2015. This research is quantitative research and using secondary data which are using a Total deposits, CAR, ROA, and FDR. The analysis that used in this research is a path analysis that can explain the patterns of relations between exogenous and endogenous variables in order to determine the directly or indirectly effect between the DPK and the CAR to ROA and it will also allow testing of FDR variables. A classic assumption test result shows that the regression results are used to qualify for the classical assumption test. This results indicate that the variable DPK, CAR, and FDR simultaneously giving a positive and significant impact on ROA. However, in partial DPK and CAR have a negative and significant impact on ROA. While FDR has a positive and significant impact on ROA. Based on the Sobel Test result, FDR is not able to act as an intervening variable but it only able to act as an exogenous variable. To support the increasing profitability, the Islamic banking must have a strategy in its function as an investment manager and distributing the funds which is too expansive on credit-based financing in a carefuly way. Islamic banks are advised too add its capital in order to raise the quality of Islamic bank’s service which is adressed to the general public.