Most capital structure studies to date are based on data from developed countries’ firms and very few studies provide evidence from developing countries. Capital structure of Microfinance banks in Kenya has not been investigated; there is no clear understanding on how microfinance banks construct their capital structure and what internal (firm-specific) factors influence their corporate financing decision. This study attempted to fill this gap by analyzing the capital structure for microfinance banks in Kenya. Guiding study objectives were; to determine influence of Profitability, Tangibility, firm Size, Age, Business risks, Capital Adequacy and Tax-Shield) on capital structure of Microfinance banks. The study was guided by static trade off theory, agency theory, pecking order theory and bankruptcy theory. A sample of three major microfinance banks was selected and secondary data were collected. Consequently, multivariate regression analysis was made based on financial statement data of the selected microfinance banks over the five year period. The findings of the study indicated that (size, age and profitability, business risks and capital adequacy) variables are the significant firm level determinants of capital structure in Kenyan microfinance banks (p