Capital adequacy plays an important role for reducing different risk components in banking industry. In this paper, we present an empirical study to measure the impact of financial and macro economical factors on capital adequacy. We gather the necessary information from financial statements and balance sheets of nine Iranian private banks over the period of 2005-2011. The results of analyzing the data based on the implementation of linear regression technique reveal that there are some meaningful relationship between financial figures, including bank size and profitability, and capital adequacy. However, the survey does not show any relationship between macro economical factors, including growth domestic product and inflations, and capital adequacy.