This research has analysed information related to the relationship of CAR data (Capital Adequacy Ratio), FDR (Financial Deposit Ratio), NPF (Non-Performance Finance), and OER (Operational Efficiency Ratio) to ROA (Return On Assets) at eleven (11) Islamic banks in Indonesia in the period 2013 to 2018. The data used is quarterly reports of Islamic Banks in the period 2009 to 2018. The results of this study shows that CAR has a positive effect on ROA which is very significant, with p-value 2.03e-10, CAR coefficient = +0.0440045, so that every increase of 1% CAR results in an increase in ROA of 0.0440045%. For NPF, it has a negative effect on ROA and is not significant, with p-value 0.6418, the coefficient of NPF = −0.0267854, so that every increase in NPF 1% results in a decrease in ROA of 0.0267854%, and vice versa. For OER, it has a negative effect on ROA significantly, with p-value 1.71e-88, OER coefficient = −0.118434, so that every increase in OER of 1% results in a decrease in ROA of 0.118434%, and vice versa. For FDR, it has a negative effect on ROA significantly with p-value 0.0001, the coefficient of FDR = .00.0124499, so that every increase in FDR of 1% results in a decrease in ROA of 0.0124499%, and vice versa.