The purpose of this study was to examine the determination of mudharabah financing in Islamic banking of Indonesia. The data used in this study were sourced from 11 Islamic Commercial Banks with a period of 2012-2016. Methods of data analysis using panel data regression and was simulated using eviews 10. After conducting the Chow test and Hausman test reveal that the random effect model was the appropriate model choose, due to partially the capital has no effect on mudharabah financing, while mudharabah savings and mudharabah deposits have a significant effect and positive for mudharabah financing. On the other hand mutually, the capital, mudharabah savings and mudharabah deposits have a significant and positive effect on mudharabah financing.