The Bank is essentialy an entity that collects funds from the public in the form of financing or in other words performs as a financial intermediation. This study aims to analyze the factors that affect the level of intermediation on islamic banks in Indonesia. The Type of data used in this is secondary data obtained from the Financial Services Authority. Methods in this study using Multiple Linier Regressions with Ordinary Least Square (OLS) methode. Variable Financing to Deposit Ratio (FDR) as dependent variable while Third Party Fund (DPK), Financing Non Performing (NPF), Retun On Assets (ROA) and Capital Adequacy Ratio (CAR) as independen variable. These are used to lookj at the factors that affect the level of intermediatios on islamic banks in Indonesia. This study used monthly data of 2012 until 2017. The result of this study showed that DPK and ROA variables have positive and significant effect on FDR while NPF and CAR variables have negative and significant effect on FDR. Thus, the suggestion in this study for islamic banking in Indonesia to bbe relatively healthy and not ignoring the principle of prudence is by increasing the FDR.