Fintech has changed the world financial architecture bringing about some benefits as well as challenges. The capital structure of organisations in recent times has undergone some adjustments due to the introduction of fintech into financial ecosystem of businesses. This study explored the relationship between fintech development and corporate financing of listed firms in Nigeria. The study specifically examined the impact of fintech on equities, corporate bonds and all share index of listed firms in Nigeria from 2009-2024. Data on fintech proxies (ATM, mobilepay, POS and webpay) and proxies of corporate financing (equities, corporate bonds and all share index) were obtained from Central Bank of Nigeria (CBN) statistical bulletin for 2024. An ex post facto research design was adopted for the study in which secondary data were used and ordinary least square (OLS) estimation technique in multiple regression model was employed to estimate the relationship among the variables of interest. Findings revealed significant impact of fintech proxies (POS and mobilepay) on equity and all share index while there was no significant impact of fintech on corporate bonds. The conclusion is that, since corporate bonds is sparingly used as corporate financing structure, the impact of fintech on it may not be feasible at the moment. It was also concluded that fintech reduces transaction cost and promote efficiency. Yet, there are challenges as well including cybercrime, resistant to change, poor fintech infrastructure among others. However, it was recommended that, there should be effective legislative and regulatory framework to contain with cyber-crime along with users’ education to boost the confidence of users on the new technology.