The formation of optimal capital structure is considered as one of the most difficult challenges that face management at banks, by exploring the capital structure at Syrian private banks, the researcher noticed that Syrian private banks depend on short term debt financing, however, the researcher sees that this kind of debt will have a weak impact on the profitability of Syrian private banks for not having long term debt financing. Thus this study discussed the impact of capital structure on profitability at Syrian Private Banks, it answered questions where if there were a significant impact of retention ratio, debt ratio, and leverage ratio on profitability measured by return on assets, return on equity, and net investment margin.