The purpose of this study was to determine of profitablity in mediating the effect on firm size and capital structure on firm value. The object of this research use islamic banking listed in Financial Services Authority (OJK) during 2014-2020. Purposive sampling technique used to determine samples and obtained 84 that met criteria. Data were analyzed using multiple linear regression analysis. The result of this study showed firm size has positive effect on profitability, while capital structure has negative effect on profitability. Meanwhile, firm size has positive effect and capital structure has negative effect on firm value. Profitability is able to mediate the effect of firm size on firm value and profitability is able to mediate the effect of capital structure on firm value.